The sample size is probably too small to mean anything, but Alex Rodriguez has been much better at the plate this season when he DH’s.
Overall A-Rod has shown his age this season. In 87 games overall he is hitting .270/.353/.442 which is good for a solid 111 OPS+. When he DH’s those numbers jump to .344/.404/.516 over 24 games and 104 plate appearances. While in the field he hits .243/.337/.417 in 60 games and 264 plate appearances.
This sort of variances are typical in baseball stats when there aren’t enough data points, but it could be an early sign that A-Rod needs more regular rest. Or that he simply focuses better these days when he’s not worried about defense.
Historically, A-Rod never played nearly as much DH as he does these days, but his splits are pretty even before this year. In his career at third he has hit .293/.388/.543 and .305/.392/.564 overall a the DH. Those numbers are similar which suggests that this has been a more recent issue. Or that it is just statistical variance.
In the field A-Rod has slowed a bit, dropping from an 11.0 UZR last season to a -2.5 so far this season. That’s not completely out of the norm for him though as he has put up seasons of -6.0 and -1.8 recently and only had one other positive UZR season before 2011 with the Yankees. So his defense has not become a problem yet. Apparently the only problem he has playing third base is when he’s in the batter’s box.