Detroit Tigers vs. Seattle Mariners: ALDS Preview

For the first time since 2020, there’s a new team atop the American League West. The Seattle Mariners took home the division, finishing 90-72, and the first of their challenges is just a day away, as they take on the Detroit Tigers.

For the Mariners, they enter the Postseason with arguably the best rotation in the sport, and one of the best overall rosters they’ve had in recent memory. Even with the first-round bye, they’ll still be one of the most feared teams in October play.

For the Detroit Tigers, this matchup is a chance to really make a statement against a juggernaut. After conquering their biggest rival, the Cleveland Guardians, this matchup is a chance to prove that they’re the team we saw earlier in this season.

For many of these players, it’ll be their first time playing in Postseason action. Every matchup, every play, and every moment has a chance to be historic and remembered for generations, and this matchup is no different.

Without further ado, let’s break down this exciting ALDS matchup and see how it may turn out.

Starting Pitching Matchups

*Matchups are educated guesses based on both teams’ rotations.*

Game 1: Logan Gilbert vs. Keider Montero

• Logan Gilbert (SEA): 25 GS, 6-6, 3.44 ERA, 3.35 FIP, 32.3 K%, 5.8 BB%, 2.6 fWAR
• Keider Montero (DET): 12 GS, 5-3, 4.37 ERA, 4.93 FIP, 18.5 K%, 8.0 BB%, 0.1 fWAR

After spending some time on the injured list this season with a right elbow flexor strain, Logan Gilbert is back to his dominant ways. Gilbert will likely be the choice for game one, as all signs indicate him and Kirby getting the ball before Bryan Woo.

Gilbert is the second incredibly lethal member of this Mariners rotation, as his ability to be a commanding presence on the mound is something the team has valued since he debuted.

Gilbert finished sixth in Cy Young voting just a season ago, and he’s followed that up with similar production during the time he’s been healthy. Gilbert struck out an astounding 173 batters in just 131 innings pitched, keeping his WHIP low, as it finished just above 1.00.

The key for the Tigers will be to avoid strikeouts and to put the ball in play as often as possible. Gilbert struggled to keep hard contact to a minimum this season, as his average exit velocity of 90.8 was one of the highest marks in the sport. If they can put good swings on Gilbert’s pitches, this will be incredibly important in how they jump on him early.

During last year’s playoff run, the Detroit Tigers made good use of openers in a few games. With it still being relatively unclear who they’ll be running out in game one, it seems possible they may turn to this once again, throwing Keider Montero as their first opener this postseason.

Montero is an interesting choice if they do decide to take the opener route. He’s made more appearances as a starter than a reliever this year, and he’s done far better as a starter. Montero has pitched to an ERA of 3.72 as a starting pitcher, a mark nearly two points lower than his ERA as a reliever.

For the Seattle Mariners, it’ll be important to work Montero’s pitch count, forcing him to throw strikes. He ranked in the bottom 11% this season in whiff rate, meaning the Mariners likely won’t have a problem expanding the strike zone. With his fastball registering a run value of -8 this year, in-zone fastballs will be his biggest weakness.

Although it’s unclear who will take the hill for either team in game one, this is going to be the beginning of quite an interesting matchup. The first game is usually the most important for momentum purposes, making this a must-win game for both teams.

Game 2: George Kirby vs. Tarik Skubal

• George Kirby (SEA): 23 GS, 10-8, 4.21 ERA, 3.37 FIP, 26.1 K%, 5.5 BB%, 2.4 fWAR
• Tarik Skubal (DET): 31 GS, 13-6, 2.21 ERA, 2.45 FIP, 32.2 K%, 4.4 BB%, 6.6 fWAR

After being one of the best right-handers in the sport for a few seasons, George Kirby struggled in his 23 starts this season. However, Kirby still has the ability to dominate in big game scenarios and make a significant impact for the Seattle Mariners during his start.

Kirby, a former All-Star, will be a tough pitcher to beat. He’s found success in his limited playoff experience in the past, throwing eight scoreless innings across two games. This is another chance for Kirby to showcase his big-game skills, helping the Mariners lock down game three of this series.

Throughout his career, Kirby’s calling card has been his ability to limit free passes, keeping unnecessary runners off the bases. While this is still relatively true, his walk rate increased 2.5% this season. Forcing Kirby into tougher counts will be one of the keys to their success. Especially if they can force him to rely more on his sinker, which generated an opponent xwOBA of .364 this season.

For the Detroit Tigers, they’ll be sending arguably the best starting pitcher in the sport to the mound in Tarik Skubal. After winning his first career Cy Young Award last season, Skubal has the chance to win the award for the second time after having yet another tremendous season.

Dominating on all cylinders, Skubal will be the toughest member of the Tigers’ rotation to overcome. Now in his second year of postseason experience, he’s proven himself to be a big-game pitcher. He threw 7.2 innings of one-run baseball while striking out 14 against the Guardians, a performance that really helped the Tigers make a statement in this series.

Attacking Skubal will be a tall task for the Seattle Mariners, as he has almost no weak points. The only area where Skubal remains somewhat beatable is with his sinker. Throwing it 23.7% of the time this year, it’s generated an xwOBA of .325, a solid number, but less elite than the rest of his arsenal.

This matchup has the chance to be the best pitching matchup in the whole series. With the Tigers sending one of the best arms in the sport to the mound, and the Mariners sending one of their best pitchers to the mound, a pitching duel could certainly be in the cards.

Game 3: Bryan Woo vs. Casey Mize

• Bryan Woo (SEA): 30 GS, 15-7, 2.94 ERA, 3.47 FIP, 27.1 K%, 4.9 BB%, 3.6 fWAR
• Casey Mize (DET): 28 GS, 14-6, 3.87 ERA, 3.89 FIP, 22.2 K%, 5.7 BB%, 2.4 fWAR

For the Seattle Mariners, the choice for game three is likely going to be their ace Bryan Woo. After finishing the regular season as one of the best right-handers in the American League, Woo would be a scary opponent for the Tigers. Woo didn’t face the Tigers at all this season, making this quite the moment for them to meet for the first time.

After making his first career All-Star team this season, Woo dealt with some pec injuries down the stretch for the Mariners. While he looks to be healthy and ready to go for game one, this injury could be something to keep an eye on in case Woo isn’t feeling exactly like himself.

One thing is for certain: Woo is incredibly consistent. Out of his 30 starts this season, Woo had 21 quality starts, a number that tied him for second in the league. The key for the Tigers will be to jump on him early and force the Mariners to go to their bullpen as quickly as possible.

The expectations surrounding Tigers right-hander Casey Mize have been high since the moment he joined the organization. Although it took the former first-overall pick some time to come into his own, his breakout 2025 season has been very fun to watch.

Mize was selected to his first All-Star team this year due to his hot start, and he deserved every bit of this recognition. Pitching to an ERA of 3.87 across 28 starts, Mize has been a stable option for the Tigers to turn to. He’s been quite the reliable weapon, keeping the score close in most of his starts.

Although 2025 has been a relatively positive season for Mize, he remains beatable for the Mariners. Mize’s secondary offering has been his splitter, which has been abysmal this season. Registering a -11 run value, if the Mariners can capitalize on his struggles with the pitch, they’ll be in a good position.

It’ll be tough to predict how this pitching matchup will play out, as both arms have their pros and cons. Due to this, it’s possible that this game would be determined by the offenses and less by the starting pitchers.

Game 4 (If Needed): Bryce Miller vs. Jack Flaherty

• Bryce Miller (SEA): 18 GS, 4-6, 5.68 ERA, 5.17 FIP, 18.9 K%, 8.7 BB%, 0.0 fWAR
• Jack Flaherty (DET): 31 GS, 8-15, 4.64 ERA, 3.85 FIP, 27.6 K%, 8.7 BB%, 2.5 fWAR

While there’s no guaranteed fourth game in this matchup, it seems likely the Seattle Mariners will opt to go with Bryce Miller if necessary. After breaking in 2024, Miller looked more human this year, as he was regularly challenged in the time he was on the field.

Some of Miller’s struggles can be attributed to the fact that he battled injuries throughout a good portion of the 2025 season. From elbow inflammation to a bone spur, Miller’s health regularly led to stints on the injured list. However, at full strength in 2024, he was dominant.

Miller significantly struggled to limit hard contact this season. His average exit velocity and hard-hit rate ranked in the bottom two percent of the league, leading to some potential concerns for extra-base hits. For the Tigers, maximizing these struggles will be one of their keys to success.

The 2025 season has been a tale of significant ups and downs for Jack Flaherty. After coming back to Detroit in the offseason, Flaherty has struggled a lot more during his second stint with the team than he did during his last stint with the club.

Throughout 31 starts, Flaherty pitched to an ERA over 4.60, struggling to limit hard contact along the way. Despite his struggles on the surface, Flaherty has still posted solid strikeout numbers, leaving the Tigers with some positive takeaways from his starts.

Flaherty’s struggles to limit hard contact will be the aspect of his game the Mariners must capitalize on. With the Mariners hitting the third most homers in the sport this year, this could end up being Flaherty’s downfall.

If the series reaches this point, the pitching matchup will make or break who wins the series. Whether Flaherty and Castillo dominate or struggle could completely change whether or not each team advances or heads home for the offseason.

Game 5 (If Needed): Luis Castillo vs. Tarik Skubal

• Luis Castillo (SEA): 32 GS, 11-8, 3.54 ERA, 3.88 FIP, 21.7 K%, 6.2 BB%, 2.6 fWAR
• Tarik Skubal (DET): 31 GS, 13-6, 2.21 ERA, 2.45 FIP, 32.2 K%, 4.4 BB%, 6.6 fWAR

One of the best parts of the Mariners’ squad is how deep their rotation is, and this will be even more evident if the series runs five games. Instead of turning to a weaker starter near the end of the series, the Mariners will have the luxury of relying on three-time All-Star Luis Castillo in game five.

Luis Castillo is coming off a very solid 2025 campaign, where he saw himself pitch like one of the more consistent starters in baseball. He lowered his ERA and FIP from the 2024 season, becoming an even more reliable innings-eater for the club.

However, despite his consistency, there are areas where Castillo is weak. Similar to the other members of this rotation, Castillo has struggled to limit hard contact, as his barrel rate ranked in the bottom 17% of the league. Also, Castillo has run into struggles with his sinker, which has resulted in an opponent xwOBA of .375. For the Tigers, using these weak points will be key to their success.

The biggest strength of the Detroit Tigers is Tarik Skubal. Luckily, based on off-days, Skubal can start on regular rest for both Game 2 and Game 5 of this series.

Now with the all-hands-on-deck nature of the postseason, we are likely to see many starting pitchers enter games in relief, making it very unlikely that the Mariners will run their full five-man rotation in this series. We laid it out this way to show that they have the depth to be able to do so.

For the Tigers, it is pretty much Skubal, a good bullpen, and hoping you can steal four innings from Mize or Flaherty whenever they take the ball. Luckily, if the Tigers can steal a non-Skubal game and win the two when he takes the mound, that would be enough to advance.

Key Storylines To Watch: Seattle Mariners

Can Julio Rodriguez Stay Hot in the Second Half?

After a relatively disappointing first half of the season, Julio Rodriguez proceeded to have an incredible second half, salvaging his season. He posted a wRC+ 42 points higher during the second half of the season, becoming the version of himself the team expected.

Rodriguez has also had some success in the five postseason games he’s played prior to this series. He registered a 127 wRC+ in this stint, while driving in two runs in the process. Knowing how hot he’s entering October and the success he’s had before, this mix could be dangerous.

One of the biggest questions for the Mariners’ offense will be whether or not Rodriguez can continue to ride out this hot streak. If Rodriguez can remain hot, he’ll be a tough out for the Tigers every time he comes to the plate.

Stability from the Bullpen

The Seattle Mariners have been widely known for the success of their rotation during the 2025 season, but their bullpen has quietly been very good. Posting the ninth-best bullpen ERA in the sport, their relievers have done a fantastic job backing up the success of the rotation.

This is largely thanks to Andres Munoz, the team’s closer, who finished third in baseball with 38 saves. Their bullpen success runs deeper than Munoz, though, as Luke Jackson, Matt Brash, and Eduardo Bazardo have all registered ERAs under 3.00.

If the Seattle Mariners want any chance at making a deep postseason run, they need to find stable innings from their entire bullpen, not just their highest leverage arms. If the bullpen can back up their rotation, look out.

Which Version of Cal Raleigh Will the Mariners Get?

Cal Raleigh is coming off a season full of headlines. Raleigh became the first catcher ever to hit 60 home runs, took home a Home Run Derby Championship, and was named to his first All-Star team. However, despite the overwhelming good that came from Raleigh’s season, he went through some significant ups and downs.

Before a red-hot September, Raleigh slashed just .173/.308/.449 during August, a significant step down from his production earlier in the season. Although this was still good for a 116 wRC+, his strikeout rate jumped to an astounding 33.3% during this stretch.

At his best, Raleigh was a 60 home run hitter and one of the most feared power hitters in the sport. However, at his worst, Raleigh struggled to keep his strikeouts down, and he struggled to get on base consistently. If the Mariners want any shot at advancing, they need the red-hot Raleigh from September to show up big.

Key Storylines To Watch: Detroit Tigers

Will the Tigers’ Use of the Opener Work?

Throughout their recent postseason appearances, the Detroit Tigers have heavily relied on the use of the opener, an interesting strategy to employ at such a pivotal time in the season. All signs are pointing towards the Tigers using a similar strategy in this series.

It looks like the Tigers will use two openers during this series, Troy Melton and Keider Montero. With these two starters projected to throw early in the series, how they pitch could set the tone for the entire series. If they throw well and the bullpen backs up their performances, the Tigers will look like geniuses. If not, the Tigers will be put in a difficult position later in the series.

It remains quite interesting to see the Tigers rely so heavily on the opener during pivotal playoff games, but it has worked well for them in the past. Regardless, this will be a huge part of this series.

Skubal’s Postseason Success

Throughout the last two seasons, the Detroit Tigers have relied heavily on the success of Tarik Skubal to carry them through tough playoff games. Skubal already threw 7.2 scoreless innings against the Guardians this season, and he has a career ERA slightly over 2.00 in nearly 27 playoff innings.

With the Mariners’ lineup being one of the best in the sport and Skubal’s playoff successes, something is bound to give. For the Tigers, they’ll be hoping it’s the Mariners’ lineup that cracks and not Skubal.

Can El Mago Stay Hot?

This season, one of the best early storylines was the career revival of Javier Baez. After signing a six-year, $140 million deal back in 2021, Baez saw his offensive numbers take a drastic fall to the bottom of the leaderboards. However, this year, things have been different, and they’ve carried into October.

During the Wild Card matchup against the Cleveland Guardians, Javier Baez went 5-11 with a double and an RBI, being one of the key pieces of their offense along the way. This has been a positive change to see, as Baez has posted a wRC+ of only 74 throughout 38 postseason games.

In order for the Tigers to overcome the Seattle Mariners and their elite pitching staff, they’ll need Baez to stay hot. If Baez can get on base and be driven in by the top of the order, they’ll be in good shape.

Prediction

Mariners in Four

After examining the matchup more closely, I believe the Seattle Mariners will take this matchup in four games. With their offense ranking in the top three in wRC+ and home runs alongside a truly dominant rotation, they’ll be one of the toughest teams to handle in the postseason.

The Tigers entered October narrowly avoiding one of the worst collapses in baseball history, as they had baseball’s worst record during September. Taking this into consideration, as well as the fact that they’ll likely use the opener in two games, it feels much safer to choose the Mariners to win.

The reason I chose four games is that I believe the Mariners will have a tough time taking on Tarik Skubal during the playoffs. They hit him fairly well during the two games they faced off this season, but Skubal is a completely different pitcher during the postseason.

Overall, the Mariners will ride their elite pitching staff and one of the best offenses in baseball to victory.