The Boston Red Sox have made their first notable move to shore up the roster this offseason, bringing in veteran Willson Contreras - a name that carries both power at the plate and, now, surprising upside in the field. After years behind the plate, Contreras is transitioning into a first base/designated hitter role, and early signs suggest he might be more than just serviceable in his new spot.
Contreras, acquired from the Cardinals in what marks Boston’s third trade with St. Louis since the 2025 deadline, is expected to split time between first base and DH in 2026.
And while this will be his first full season playing the corner infield, the numbers from his limited time there are promising. He posted six outs above average and ranked in the 91st percentile in range - a significant step forward defensively for a player long known for his work behind the dish.
That’s a massive upgrade when you compare him to Boston’s recent options at first base. Triston Casas, once considered the future at the position, struggled mightily on defense in 2023, logging -10 OAA and landing in the second percentile in range.
Pete Alonso, a free agent target for Boston, didn’t fare much better with -9 OAA and the same percentile range. Simply put: Contreras brings a level of defensive competence that’s been missing from the Red Sox infield for a while.
Injuries have played a big role in that instability. Casas has battled through a string of setbacks, forcing the Sox to turn to patchwork solutions like Dominic Smith and Abraham Toro.
Neither provided the kind of consistency Boston needs at first base - especially for a team trying to clean up its defensive act after leading MLB in errors last season with 116. Most of those miscues came from the infield, and the issues were especially glaring at first and second base.
That’s where Contreras could make a real difference. His presence alone helps stabilize the right side of the infield, and when paired with a potential reunion with Alex Bregman at third base, Boston could finally field a corner infield that’s both reliable and dynamic.
Bregman, despite a bit of a down year defensively by his standards - nine errors - still brings elite range to the hot corner, ranking in the 83rd percentile with three outs above average. That’s a clear upgrade over Rafael Devers, who has long been known more for his bat than his glove. A healthy Bregman anchoring third base could be a game-changer for Boston, especially if he returns to his usual form after an uneven 2025.
Meanwhile, the Red Sox are sticking with Trevor Story at shortstop for 2026, banking on a rebound after a rocky defensive season. Story made 19 errors, but considering he hadn’t played a full season in three years, some rust was inevitable. Even a modest bounce-back would go a long way toward tightening up the middle infield.
With Story locked in at short, second base becomes the next piece of the puzzle - and that’s where Marcelo Mayer enters the conversation. Mayer’s defensive polish is already turning heads, and while his arm strength (26th percentile) may not be ideal for shortstop, it plays much better on the right side of the infield. Compared to Kristian Campbell, Mayer offers smoother defense and a higher ceiling, giving Boston a compelling option to round out the infield.
As for Casas, he’s not out of the picture. With Contreras expected to DH on occasion, there will still be opportunities for the young slugger to get reps at first base.
But giving him more time off his feet could be exactly what he needs to stay healthy and productive. The key is balance - and having Contreras in the mix allows Boston to manage Casas’ workload while raising the defensive floor.
Bottom line: if the Red Sox want to stop the bleeding defensively, especially on the infield, this is the blueprint. Contreras brings a reliable glove and veteran presence to first base.
A healthy Bregman at third could solidify the corners. Mayer’s glove gives them upside at second.
And if Story can rebound, Boston might finally have an infield that doesn’t just survive - it wins games. But to get there, re-signing Bregman isn’t just a smart move.
It’s a necessary one.