The Diamondbacks announced that first baseman Christian Walker has been reinstated from the injured list. He has been out since the end of July due to a strained left oblique. He’ll take the roster spot of outfielder Lourdes Gurriel Jr., who is heading the other way. Gurriel has been placed on the 10-day IL due to a strained left calf, retroactive to Sept. 2.
The Snakes get one of their lineup regulars back but lose another. Walker hit 23 home runs and produced a batting line of .254/.338/.476 before landing on the IL, production that translated to a 122 wRC+. He also routinely gets strong grades for his defense at first base, so he’s been worth 2.7 wins above replacement on the year despite his absence, per the calculations of FanGraphs.
Gurriel departed Sunday game due to some tightness in his calf and was sent for an MRI. It’s unclear exactly how much time the club expects him to miss, but the IL placement suggests he needs at least a week or so to rest up. He has 17 home runs and a line of .274/.316/.428 this year, leading to a 104 wRC+. He has strong defensive grades in the outfield as well, leading to a 1.8 fWAR tally on the year.
Subbing in Walker for Gurriel is a slight upgrade for the club in a vacuum, but it will be an interesting roster fit for manager Torey Lovullo to work out. The Snakes acquired Josh Bell to help cover first base in Walker’s absence and he has played well since that trade, with a .283/.356/.453 line and 125 wRC+. The designated hitter slot is usually taken by Joc Pederson, who is hitting .280/.400/.533 for a 157 wRC+ this year.
Pederson is faring well in his limited looks against southpaws this year but has notable career splits and has generally been shielded from opposing lefties. Bell is a switch-hitter and should at least be able to take the short side of a platoon with Pederson, but it’s unclear if he’ll be able to get more playing time beyond that. Pederson is a poor defender and hasn’t been put out into the field at all this year. He got 204 innings in the field with the Giants last year but produced -5 Defensive Runs Saved and -4 Outs Above Average in that limited time.
With Gurriel out, the Snakes have an opportunity to move Pederson out there while opening the DH slot for Bell/Walker, but they will have to weigh the defensive hit against the offensive gain. Randal Grichuk has strong numbers against lefty pitchers this year, 128 wRC+ against them compared to a 96 wRC+ without the platoon advantage. Theoretically, he could take the field against southpaws with Bell as the DH, then Pederson could take the field against righties. Although perhaps they might simply prefer to have Grichuk out there since he’s a stronger defender than Pederson, perhaps factoring in the pitcher and opposing lineup, calculating whether they think the left fielder will see a lot of action on a given day.