Diamondbacks Need Successful Home Series vs Mariners

The Arizona Diamondbacks appeared to be clawing their way back into contention after a three-game sweep of the Atlanta Braves, but that momentum did not continue in a gloomy sweep at the hands of the Cincinnati Reds.

With their record fallen to 31-34, Arizona will return to Chase Field to face a struggling Seattle Mariners club at Chase Field.

The Mariners are 33-31, and have lost seven of their last 10 games, including dropping two of three to the Angels this week. With both Arizona and Seattle in search of a get-right series, a three-game set in Phoenix could provide either a necessary boost or plunge the D-backs further into a hole.

Pitching Matchups

Monday, June 9, 6:40 p.m. MST

RHP Merrill Kelly vs RHP Emerson Hancock

Merrill Kelly has suffered a few rough outings of late, but that hasn't truly derailed the veteran righty's excellent season. He's pitched to a 3.43 ERA and 3.33 FIP in 13 starts, and was brilliant against the Atlanta Braves his last time out. Kelly spun seven masterful innings, taking a no-hitter into the sixth inning and punching out nine.

Kelly has only faced the Mariners once before — back in 2023. He gave up three runs on seven hits and took the loss despite striking out six over five innings.

Young right-hander Emerson Hancock struggled to open the year, but has steadily lowered his ERA in each of his last four starts. He hasn't gone particularly deep in games and has struggled to collect strikeouts, but he hasn't allowed more than three runs in a game since May 12.

The Diamondbacks have seen Hancock once, and were held to just one run on two hits over six innings back in April of 2024.

Tuesday, June 10, 6:40 p.m. MST

RHP Brandon Pfaadt vs RHP Bryan Woo

Brandon Pfaadt has looked nothing like the pitcher the D-backs believed him to be in recent starts. Two turns ago, he suffered a career-worst outing in which he gave up eight runs without recording a single out. The woes continued for Pfaadt his last time out, as he gave up six runs (five earned) in just three innings against the Braves.

Pfaadt delivered a six-inning Quality Start against the Mariners in early 2024, allowing two runs and striking out an impressive 11 batters.

Young righty Bryan Woo has been an excellent arm for Seattle this season, as he's pitched to a 3.07 ERA and 3.30 FIP in 12 starts. He's been knocked around a but in his past two starts, giving up seven runs over 12.2 innings, however.

Woo has only seen the D-backs once, allowing three runs on seven hits over five innings in his 2023 rookie season. Woo has gone into the sixth inning or later in every single start to open 2025, and has pitched into the seventh six times. He has nine Quality starts.

Wednesday, June 11, 12:40 p.m. MST

LHP Eduardo Rodríguez vs RHP Bryce Miller

Eduardo Rodríguez has seen some poor luck, but has also pitched relatively poorly in 2025. His 6.70 ERA is an ugly figure, though it's backed up by a 4.30 FIP and 4.15 expected ERA.

Rodríguez spent some time down on the 15-day IL with left shoulder inflammation, and was solid enough in his return debut on Friday. He allowed two earned runs on a two-run homer and struck out three without walking a batter, but he did allow six hits in five innings.

Rodríguez has seen the Mariners many times in his time in the American League, and has a 4.03 ERA against the club. Most recently, he allowed two runs over five innings and got the win in 2023.

Bryce Miller had an excellent sophomore season in 2024 but has hit a bit of a wall in 2025. That said, his 4.40 FIP does suggest his 5.73 ERA might be a bit inflated.

Still, he's been hittable, and has issued far more walks than previous seasons. He was roughed up for five runs in five innings against the Angels on June 6. Miller has never faced the D-backs in his young career.

Offenses

The Mariners don't exactly have a terrifying lineup of hitters, but star catcher Cal Raleigh has been a serious weapon. The switch-hitting Raleigh holds the MLB lead in home runs with 26, and is slashing an immense .272/.380/.655 for a 1.035 OPS. When he makes contact, it goes far.

Julio Rodríguez is making good contact with a .308 average to begin June, but has just one extra-base hit. Randy Arozarena is hitting just .228 on the year with a .730 OPS.

For the D-backs, the offense has been silent since their outburst against Atlanta. Ketel Marte has a 1.446 OPS to open June and has homered four times this month. Eugenio Suárez homered twice in Cincinnati and has 18 on the year. Corbin Carroll appeared to be entering a slump, but has 18 homers of his own in 2025 including two in game one against the Braves. His OPS is .904.

Bullpens

Arizona finds itself once again in a lopsided relief comparison. The D-backs' 5.28 bullpen ERA is 27th in MLB, while the Mariners rank 14th with a 3.74 reliever ERA.

While the D-backs have seen the return of flamethrower Justin Martinez, and some positive regression from Jalen Beeks and Shelby Miller, there is still a distinct disadvantage present. Arizona should have all of their high-leverage options available for the series opener.

For Seattle, Andrés Muñoz has been one of the best closers in baseball in 2025. He's thrown to a 1.25 ERA and is 18-for-22 in save opportunities. The Mariners called on Muñoz and setup man Matt Brash Sunday, but the two combined to throw just 36 pitches. The rest of Seattle's high-leverage bullpen is rested.