Here is a look at every team’s most impactful newcomer acquired in the offseason for 2018. Keep in mind this is only for the 2018 season with the major league club. There are prospects that may have much more impact in the long-term, but will be toiling in the minors for all or most of next year.
American League
Baltimore Orioles - Nestor Cortes, relief pitcher
Cortes was taken in the Rule 5 Draft from the Yankees in December. While he may not start the season with Baltimore and has never pitched at the major league level, there is a good chance he will be seen at some point.
In 11 appearances (six starts) at AAA last year, he had a 1.49 ERA and 57 strikeouts in 48.1 innings.
Boston Red Sox - Ivan De Jesus Jr., infielder
While many believe the Red Sox will sign J. D. Martinez eventually, it is reasonable to say that no current newcomers from this offseason to their club will be on their Opening Day roster. Perhaps De Jesus Jr., a non-roster invite, impresses enough to make it especially if Dustin Pedroia is not ready to begin the season. He stayed in the minors in 2017 and hit .253 in 243 plate appearances with the Reds in 2016.
Chicago White Sox - Welington Castillo, catcher
Castillo was one of the better offensive catchers in baseball for the Orioles in 2017. In 96 games, he hit for a .282 average with 20 home runs.
Cleveland Indians - Yonder Alonso, first baseman
Alonso will take over as the starting first baseman for the departed Carlos Santana. He made his first All-Star Game in 2017 and hit a career-high 28 home runs with the Athletics and Mariners (previous high was nine).
Detroit Tigers - Mike Fiers, starting pitcher
Fiers struggled with a 5.22 ERA in 28 starts with the Astros in 2017.
He did have a 3.74 ERA in 76 games (70 starts) from 2014-16 though. He will start the year in the rotation for the rebuilding Tigers.
Houston Astros - Gerrit Cole, starting pitcher
The first overall selection in the 2011 Amateur Draft, Cole had a 4.26 ERA and 196 strikeouts in 33 starts. He finished fourth in National League Cy Young voting in 2015.
Kansas City Royals - Wily Peralta, starting pitcher
Peralta is looking to regain his 2014 form when he had a 3.53 ERA in 32 starts. He struggled mightily in 2017 with the Brewers posting a 7.85 ERA in 19 games (eight starts).
Los Angeles Angles - Shohei Ohtani, starting pitcher/designated hitter
Coming from Japan, Ohtani is expected to both serve as a designated hitter and starting pitcher for the Angels. With the Nippon Ham Fighters last year, he hit .332 with eight homers and 16 doubles in 231 plate appearances. He started five games finishing with a 3.20 ERA, and he has a career 2.52 ERA in Japan in 85 appearances (82 starts).
Minnesota Twins - Addison Reed, relief pitcher
Reed may be in line to save some games for the Twins in 2018.
He saved 19 games for the Mets (later traded to the Red Sox) last season and had 101 saves from 2012-14.
New York Yankees - Giancarlo Stanton, outfielder
It’s not often a reigning MVP joins a new team, but that’s what happened when Stanton was traded to the Yankees after winning National League Mvp with the Marlins in 2017. He led the majors last year with 59 homers and 132 RBIs.
Oakland Athletics - Stephen Piscotty, outfielder
Piscotty had a disappointing 2017 for the Cardinals after finishing sixth in National League Rookie of the Year voting in 2015 and hitting 22 homers and 35 doubles in 2016. He hit just .235 with nine home runs in 401 plate appearances last season.
Seattle Mariners - Dee Gordon, second baseman/outfielder
The speedy Gordon joins the Mariners after they acquired him from the Marlins.
While he has spent his career at second base, Seattle will use him in center field being they have Robinson Cano entrenched at second base. He batted .308 last season, won the National League batting title in 2015, and led the league in steals three of the past four years.
Tampa Bay Rays - Denard Span, outfielder
Span played in 129 games for the Giants in 2017 and had a .272 average with 12 homers and 31 doubles. He hit over .300 with the Nationals in both 2014 and 2015.
Texas Rangers - Mike Minor, starting pitcher
Minor will at least begin the season as a starter after an excellent 2017 in relief with the Royals. In 77.2 innings, he had a 2.55 ERA, 88 strikeouts, and a 1.02 WHIP. He started 110 games from 2010-14 with the Braves.
Toronto Blue Jays - Yangervis Solarte, second baseman
Solarte hit a career-high 18 home runs for the Padres in 2017 but also hit a career-low .255. He combined for a .277 average with 29 homers and 59 doubles in 2015-16.
National League
Arizona Diamondbacks - Brad Boxberger, relief pitcher
Boxberger had a 3.38 ERA in 29.1 innings last season for the Rays. He led the American League with 41 saves in 2015.
Atlanta Braves - Brandon McCarthy, starting pitcher
McCarthy finished with a 3.98 ERA in 19 games (16 starts) with the Dodgers in 2017. He has struggled to remain healthy recently though as he started just 13 games from 2015-16.
Chicago Cubs - Tyler Chatwood, starting pitcher
Chatwood finished 2017 with a 4.69 ERA in 33 games (25 starts) as a member of the Rockies.
He pitched much better away from Coors Field though with a 3.49 ERA in away games.
Cincinnati Reds - Jared Hughes, relief pitcher
Hughes had a strong showing in his 67 appearances with the Brewers last season. In 59.2 innings, he finished with a 3.02 ERA and 1.22 WHIP.
Colorado Rockies - Wade Davis, relief pitcher
The Rockies signed Davis to the largest annual salary ever given to a reliever when they agreed on a three-year deal worth $52 million. He saved 32 games with a 2.30 ERA for the Cubs in 2017. From 2014-16 with the Royals, Davis had 47 saves and a microscopic 1.18 ERA.
Los Angeles Dodgers - Scott Alexander, relief pitcher
Alexander was superb for the Royals in 2017 coming out of the bullpen.
In 69.0 innings, he finished with a 2.48 ERA and gave up just three home runs.
Miami Marlins - Starlin Castro, second baseman
Castro, who was acquired by the Marlins in the Giancarlo Stanton deal, has asked to be traded. For now though, Castro remains on Miami’s roster. The four-time All-Star finished 2017 batting .300 with 16 homers for the Yankees.
Milwaukee Brewers - Jhoulys Chacin, starting pitcher
Chacin put together a solid 2017 with the Padres as he had a 3.89 ERA and 1.27 WHIP in 32 starts. The ERA is right around his career mark of 3.93 in 195 appearances (167 starts).
New York Mets - Jay Bruce, outfielder
Bruce rejoins the Mets after they traded him away to the Indians last August. With the two teams, he combined to hit 36 home runs with 101 RBIs in 2017.
He has 277 career homers in his 10 seasons and has hit at least 30 five times.
Philadelphia Phillies - Carlos Santana, first baseman
While just a career .249 hitter, Santana has averaged 98.4 walks per season since 2011. He hit 23 homers and 37 doubles for the Indians last season.
Pittsburgh Pirates - Joe Musgrove, starting pitcher
Musgrove should be a part of the Pirates’ starting rotation after being utilized as both a starter and reliever in 2017 with the Astros. Last season, he appeared in 38 games (15 starts) and had a 4.77 ERA.
San Diego Padres - Chase Headley, third baseman
Headley rejoins a Padres team he played for from 2007-14. Last season with the Yankees, he hit .273 with 12 homers and 30 doubles.
He led the National League in RBIs with San Diego in 2012 with 115.
San Francisco Giants - Andrew McCutchen, outfielder
The 2013 National League MVP had a bounce-back season after a rough 2016. Last year, McCutchen hit .279 with 28 home runs and 30 doubles. He has hit at least 21 homers in each of the last seven seasons.
St. Louis Cardinals - Marcell Ozuna, outfielder
Ozuna was named an All-Star each of the last two seasons for the Marlins. Last season was his best year in the majors as he hit .312 with 37 home runs and 124 RBIs.
Washington Nationals - Matt Adams, first baseman
Adams will likely serve as Ryan Zimmerman’s backup at first base in 2018. Playing with the Cardinals and Braves last year, he batted .274 with 20 homers and 22 doubles.