"Howie's just been a little bit not quite 100 percent," Mattingly said. "He's still having to play with a little bit of a governor. We'll keep trying it and moving him forward to be 100 percent, but that's one of the main factors tonight, that and a righty [Giants starter Jake Peavy] and with Chase you don't really mind that.
"It's just that he's having some tightness and [the hamstring] is not exactly where we want it. We'd rather him feel like he's good to go every day. It hasn't quite been like that. We're being a little protective. We're going to play Howie; he feels like he can go out there."
Kendrick missed 34 games from Aug. 10 to Sept. 18. Since he's returned, Kendrick is hitting .250 with five RBIs but no extra-base hits.
In other injury updates, Mattingly said Yasiel Puig is running at 80 percent and Jose Peraza at 90 percent as they rehab hamstring injuries in Arizona.
And Brandon McCarthy, who had Tommy John surgery in late April, began playing catch.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.