It wouldn’t be a Boston Red Sox spring training without a competition for second base. Last year, Kristian Campbell ultimately won out and made the Opening Day roster but failed to make a lasting impact during the 2025 season. This year, though, it’s different. We have a general idea of who will be in the infield, just not where they will play. Obviously, Trevor Story will man shortstop, and Willson Contreras will be the starting first baseman barring injury. But that leaves two other positions with question marks as to who will be playing them in just about three weeks from now.
Marcelo Mayer and Caleb Durbin both feature the positional versatility to swap between second and third base, but as we saw with Campbell last season, shuffling young players between positions can negatively impact their experience in the big leagues. Expect to see the team lean into this mentality when it comes to both Mayer and Durbin as spring training continues. Which player needs to be at which position though? Let’s see if we can figure out the path Craig Breslow and Alex Cora may take for Opening Day.
After the team traded for Durbin, the initial belief was that he would slot into the lineup as the second baseman. The Athletic’s Jen McCaffrey also reported that the team preferred for Mayer to remain at third after he showed promising skills at the hot corner while he served as the starter in the wake of Alex Bregman’s quad injury. Now, though? Durbin hasn’t sniffed an inning at second, while Mayer has been at the keystone during both spring training starts.
On the surface, this positioning makes a lot of sense. Durbin took over the starting third base job for the Brewers after only 10 games at second in 2025. He played second for the majority of his minor-league career, but the team was confident that he’d be able to shift to his right and continue to play high-level defense at the hot corner. They ended up being correct, but things started off pretty rocky for Durbin after the switch. He settled down after a time though and became a good enough defender to go alongside his solid offensive production that he came in third in the National League Rookie of the Year voting. Keeping him in the position that he’s most recently played at the big-league level makes sense, especially during spring training. He’s spent the majority of the offseason preparing as a third baseman with the Brewers — remember, he was only traded to Boston on February 9, so shifting him back to second could stall or delay his ramp up to full time playing this spring.
Shifting our attention to Mayer, we see a young, former top prospect who is looking to prove to the organization that drafted him so high that he was worth the investment. Playing regularly at second base will give him that opportunity. Mayer has often been injured since being drafted in 2021, but he’s added weight that the team believes will help keep him healthy moving forward. In addition to the added weight, moving him from third to second should also help to keep him on the field for much of 2026. Mayer is a capable third basemen, he proved as much last season, but moving him to second helps in a number of ways. First, his arm strength leaves a bit to be desired. In 2025, it graded out in the 26th percentile. That’s iffy from across the diamond at third, but more than passable for second and eventually shortstop where he is expected to end up once Story departs the organization.
More importantly, Mayer will likely be used in a platoon role for much of the 2026 season as Cora looks to protect the young star from overpowering left-handed pitchers. He was expected to platoon with Romy Gonzalez, but a shoulder injury has put him on the shelf for the foreseeable future. Now, expect to see Mayer work in a platoon with Andruw Monasterio, another piece of the trade that brought Durbin to Boston, at second.
There could certainly be a position switch between Caleb Durbin and Marcelo Mayer as spring training continues to unwind, but it seems that Alex Cora is leaning in the direction of having Durbin at third and Mayer at second. Assume that such an alignment is the plan come Opening Day, but having two players who can flip flop positions when necessary isn’t a bad thing either.