Do The New York Mets Have The Best Middle Infield In Baseball After Acquiring Marcus Semien?

The New York Mets executed the first blockbuster deal of MLB's offseason, trading Brandon Nimmo to the Texas Rangers for Marcus Semien. One-for-one swaps involving All-Star veterans are rare, especially in the modern era, making this one of the more attention-grabbing in recent memory. Still, despite the grandiose nature of the trade, there will be meaningful on-field implications for New York and Texas. 

Nimmo will step in as the Rangers' everyday left fielder, a position primarily patrolled by budding star Wyatt Langford the previous two seasons. Langford will shift over to right field, a position higher on the defensive spectrum, which should suit the rangy corner outfielder well. Evan Carter will remain in centerfield. The trio will create one of the best outfields in the American League, with intentions of guiding Texas back to the postseason after missing it the past two seasons. 

Nimmo should continue to perform at an above-average rate for Texas. Yet, this two-player swap could prove to be much more beneficial for the Mets, who now pencil in Semien as their everyday second baseman. Since acquiring Francisco Lindor from Cleveland in 2021, the star shortstop's primary middle-infield partner has been Jeff McNeil, with the left-handed hitting veteran netting 426 starts at the position over the past five seasons. Luisangel Acuña netted 434 1/3 innings at second base last season, signaling the organization was soft-launching a permanent move off the position for McNeil. 

New York trading for Semien solidifies McNeil's move off the position, with the long-time Met expected to replace Nimmo as the club's primary left fielder. Despite being a productive hitter and commendable defender at second base over the past eight seasons, the rollercoaster nature of McNeil's performance has limited the upside of New York's middle-infield, despite rostering the best shortstop in baseball in Lindor.

Last season, the Mets produced the second-most Wins Above Replacement at FanGraphs (fWAR) at second base (4.8), trailing only the Toronto Blue Jays. The club also netted the fourth-most fWAR (6.3) at shortstop, landing behind the Philadelphia Phillies, Arizona Diamondbacks, and Kansas City Royals. Combining these two positions, New York finished third in fWAR generated by middle infielders (11.1), trailing only Philadelphia (11.2) and Arizona (11.8). 

Arizona's Ketel Marte and Geraldo Perdomo were baseball's most productive middle infield last season, an unsurprising result given that Marte is a top-five hitter in the sport (and an above-average fielder) and Perdomo is one of the best all-around shortstops in baseball. Trea Turner carried much of Philadelphia's middle infield production at the plate. Yet, Bryson Stott provided value at second base by being one of the best defensive second basemen in baseball, netting +7 Outs Above Average (OAA). 

After guiding Texas to its first World Series championship in 2023, Semien struggled at the plate the past two seasons, hitting .234/.307/.379 (96 wRC+) over a combined 1,252 plate appearances. Still, looking at his underlying metrics, the hard-hitting righty could manufacture another campaign similar to his 2023 one, wherein he hit 29 home runs and posted a 128 wRC+ over 753 plate appearances. The 35-year-old is also still one of the best defensive second basemen in baseball, evidenced by his posting +7 OAA at the position last season. Assuming Lindor continues to perform at an MVP-caliber rate and Arizona's middle infield duo undergoes some semblance of regression, a rejuvenated Semien could propel the Mets toward fielding the best middle infield in baseball.