Every MLB team's X-factor

Miller had a disastrous 2016 season after the Diamondbacks sent a haul to the Braves for him, and he tore his UCL early last season. Arizona doesn't expect Miller to return until closer to the All-Star break, but the D-backs still expect better returns on the former front office's investment. Miller had a 3.02 ERA in 33 starts for Atlanta during 2015.

Arguably the best prospect in baseball, Acuna has turned heads during spring training and could be ready now. Of course, the Braves will likely give him a couple months of minor league seasoning due to service time concerns, but he's a 20/40 man in the making.

The Orioles had an embarrassing rotation last season. Late into this offseason, they tried to remedy that issue by giving Cashner a two-year deal. It's a major risk given that Cashner had an ERA above 5.00 in 2016 and an awful 4.6 K/9 for Texas last season. Baltimore is betting on his high ground ball rate, and he will have to produce like last season (3.40 ERA) if the team has any chance of competing in a loaded AL East.

Pedroia has been a star for many years in Boston, but major knee surgery makes him a question mark for 2018. He's unlikely to be ready for Opening Day, which is one reason the Red Sox brought back Eduardo Nunez. Pedroia's leadership and on-base skills (.369 OBP in 2017) are still important to an offense that will try to keep pace with the Yankees.

The Cubs are taking a major risk heading into 2018 handing closing duties to Morrow. Morrow was terrific last season for the Dodgers, but he has limited experience as a closer and a long history of arm injuries. Based on last year's 2.06 ERA and 5.56 K/BB ratio, however, the risk could pay off in a big way.

He may not be quite ready for the majors yet, but Kopech could be the best piece of the Chris Sale return from last year that also included second baseman Yoan Moncada. Hitting triple digits on the radar gun, Kopech had a 2.88 ERA and 172 strikeouts in 134.1 innings between Double- and Triple-A last season. The sky is the limit when he does arrive.

The Reds had the worst starting pitching in the NL last season, but it looks like that could be remedied as early as this year. Luis Castillo was terrific during the second half, and if spring training is any indication, the next series of talented starters is set to arrive. Garrett struggled during his 2017 season with the Reds while fighting through injuries, but he's been basically perfect this spring. The former St. John's basketball player is legit, posting a 2.55 ERA in 144.2 innings between Double- and Triple-A in 2016.

Miller was Cleveland's X-factor late in 2016 and once again last season. That will likely continue to be the case as the team's primary setup man behind Cody Allen. Simply put, Miller has been the best left-handed reliever in baseball over the last four seasons and posted a 1.44 ERA and 95 strikeouts in 62.2 innings last season. When Cleveland has a lead through seven games, the contest is basically over as long as Miller and Allen are right.

Colorado had a surprising playoff season in 2017 and did so without much of a contribution from the shortstop position. Story went into a sophomore slump after hitting 27 homers in only 97 games during his rookie campaign, fanning an NL-leading 191 times last year. There's still reason to believe Story can rebound, and the Rockies' offense will be awfully scary if it does happen.

Acquired from the Cubs last season, Candelario is excited for his opportunity as Detroit's third baseman after being blocked by Kris Bryant in Chicago. He was a favorite of Cubs manager Joe Maddon and has been a doubles machine in the minors, hitting 45 doubles between Triple-A and the majors last year. He has enough talent to push Nicholas Castellanos to the outfield and could be a nice added piece to the Detroit offense with Miguel Cabrera showing his age last season.

It's hard to imagine the World Series winners getting better, but that could be the case in 2018 behind their offseason moves and young players. Fisher didn't contribute much in the playoffs, but the athletic outfielder is set to get an opportunity early in the season with Yuli Gurriel working his way back from hand surgery. Fisher was a 20/20 man twice in the minors and hit .318 at Triple-A last season.

Soler has been an enigma for the Cubs and Royals since signing a nine-year, $30 million contract in 2012, but there's no doubt he has potential. After struggling early last season in K.C., Soler reworked his swing in the offseason and is primed for regular at-bats between the outfield corners and DH this year. After signing Lucas Duda and bringing back Mike Moustakas, the Royals could have a legitimately strong lineup if Soler delivers on his potential.

The Angels have designed their entire roster around Ohtani, known as the Babe Ruth of Japan. Not only are they set to have a six-man rotation in part to keep Ohtani on rest similar to what he had in Japan, but the team traded C.J. Cron to help provide more at-bats for the two-way star. There's unprecedented pressure on Ohtani, even on a roster that includes Mike Trout, but the Angels should be bound for the playoffs if he delivers.

The Dodgers had terrific pitching depth last season, but some of that has been cleared out after trading Brandon McCarthy and working back Julio Urias from serious shoulder surgery. Now the pitching depth rests on Buehler, one of the best prospects in baseball. His high-90s fastball with sinking action resembles Mets star Noah Syndergaard, and the team is hoping for as many as 150 innings from the right-hander. With a rotation that includes pitchers with injury histories like Clayton Kershaw, Rich Hill and Hyun-Jin Ryu, Buehler's contribution will almost surely be needed.

Miami is in full rebuild mode, but there are some reasons for fans to visit the ballpark. One is Brinson, the primary return for Christian Yelich from Milwaukee. The center fielder is extremely athletic and a potential 20/20 man at the highest level, hitting .331-13-48 with 11 steals in only 76 games at Triple-A last season. He could be a star offensively and defensively.

Milwaukee addressed its offense and defense in the offseason with the outfield additions of Christian Yelich and Lorenzo Cain on the same day. However, pitching remains a major question mark, especially with Jimmy Nelson set to miss the start of the season following shoulder surgery. The Brewers need pitchers to step up behind Chase Anderson, and Woodruff could be up for the challenge. The young right-hander struggled during his MLB debut but has been a consistent minor league starter with a career 3.29 ERA in nearly 400 innings.

A shin injury sidelined Sano late last season and left him without the ability to work out regularly this offseason. He's arrived to spring training healthy — possibly too healthy from his weight reports. The third baseman has as much pure power as anyone in the game, but his high strikeout rate has kept his batting average lower than hoped for. The Twins need Sano to get back into playing shape quickly and deliver a big power season for a lineup that isn't deep with pop.

The Mets were terribly injured last season, including arm issues for Matz. The lefty finished with an ERA above 6.00 in only 13 starts after posting a 3.16 ERA in 28 starts over his first two years. Injuries have been a consistent problem for most of Matz's pro career, but he clearly has the potential to be a No. 2 starter if he's healthy. If the Mets can get health out of Matz, Noah Syndergaard, Jacob deGrom and Matt Harvey, they're shaping up to be scary again.

New York's roster couldn't be more loaded after acquiring Giancarlo Stanton in the offseason, but that might not be all the Yanks added. Torres is competing for the starting second base job this spring after undergoing Tommy John surgery last year. The top prospect is already an elite defender and had an .863 OPS in 55 games between Double- and Triple-A last season. If he's ready, the Yankees could be that much closer to a 100-win regular season.

Puk has turned heads this spring and could be closer to the majors than the A's thought. The sixth overall pick in the 2016 draft out of Florida, Puk had a gaudy 184 strikeouts in 125 innings between High-A and Double-A last season, showing clear ace upside. It would be foolish for a rebuilding team like Oakland to rush Puk to the majors, but we could see him by the All-Star break. He's the front-line starter the organization desperately craves.

Philadelphia's lineup is stacked after signing Carlos Santana and Rhys Hoskins' late-season power surge in 2017. The starting rotation still has major questions behind Aaron Nola and Jake Arrieta, but there is plenty of potential. Pivetta had a 6.02 ERA in 26 starts last season, but the right-hander also fanned 140 batters in 133 innings. He shows big upside with his development over the last year and could develop into a No. 2 or 3 starter behind Nola despite the struggles.

The Pirates traded stars Gerrit Cole and Andrew McCutchen during the offseason, upsetting most of their fans. The return was still formidable, especially from the Astros for Cole. Musgrove was a terrific minor league pitcher in the Houston farm system and really found himself in the bullpen last year with a 1.44 ERA in 23 appearances. He's moving back to the rotation in Pittsburgh and could put together a contribution similar to what the Pirates got from Cole last year (4.26 ERA).

The Padres apparently don't feel like they're far away from competing, recently signing Eric Hosmer to a long-term deal. If their starting rotation delivers this season, they could be right. Mitchell was sent from the Yankees to San Diego in the Chase Headley salary dump during the offseason and is set to have a rotation spot. That's long overdue after splitting time between the Yankees and Triple-A over the last few seasons.

Belt signed a five-year, $72.8 million extension before last season, but his first year of the deal was cut short due to a concussion. His injury was par for the course in a nightmarish season for the Giants, but Belt looks healthy this season. He also, quietly, showed much more power last season with 18 home runs in only 104 games. If Belt's power outburst was for real, the Giants' offense should be able to take a big step forward, also adding Andrew McCutchen and Evan Longoria in the offseason.

Finding healthy starting pitchers was a major task for the Mariners last season. They still have James Paxton and Felix Hernandez at the front of the rotation, but the rest of the group looks somewhat shaky heading into the 2018 season. One pitcher who is opening eyes is Gonzales, a former first-round pick by the Cardinals who has struggled through arm issues over the last few years. The lefty hasn't allowed a run through his first three spring training starts and could step up for a Mariners team that's looking for pitching answers.

The Cardinals are set to begin the season without Reyes, their top prospect, as he recovers from Tommy John surgery. However, the team expects the hard-throwing right-hander back as early as late April. With major questions at the back end of the bullpen, as well as their starting rotation, Reyes is set to play a key role in almost any case. If he's able to rebound quickly, the Cardinals could get back into competition in the NL Central.

Tampa Bay is set to experiment with a four-man rotation, and one of those pitchers will be Eovaldi. Returning from Tommy John surgery, Eovaldi showed elite control before his elbow injury and has looked good early in spring. The former 14-game winner brings upside, along with Blake Snell and Jake Faria, and the Rays need their rotation to be elite after losing Evan Longoria, Logan Morrison and Corey Dickerson from their lineup.

A former elite prospect, Profar has had a tough four-year stretch after major shoulder problems. He spent most of last season at Triple-A, but the Rangers have resisted trading him. Profar enters this season as a likely utility man, but he's looked very strong in early spring training with a batting average above .300. The Rangers' roster has some holes, but Profar could be a difference maker for them.

Toronto's rotation was terrific in 2016, but the Jays couldn't match that production last season with injuries like Sanchez's finger issue. He's returned healthy this season, and the Jays will rely on him to be an ace again with Marcus Stroman already having shoulder woes. An extreme ground ball pitcher, Sanchez showed improved command starting in 2016 and has only one walk in seven innings this spring.

The Nats were rumored to be interested in a catcher this offseason, and it's easy to see why given how poorly Wieters played last season. The four-time All-Star produced an awful .632 OPS and also saw his once Gold Glove defense slip. Washington's lineup and starting rotation are full of stars, but Wieters could be the final piece of the puzzle if he's able to rebound.