Blake, out since Saturday night with a deep left thigh bruise, started at first base in place of James Loney, who is hitting .163 this year and is 4-for-25 lifetime against Giants starting pitcher Jonathan Sanchez. It's Blake's first time starting at first base since Aug. 20, 2008.
"James is not rolling at all," said manager Don Mattingly. "To me, he's kind of fighting himself. He was OK in spring, but we saw things the other day, getting his hands up a little bit. This guy [Sanchez] gives him trouble and Casey's back. We need to get him going."
The concern with Loney is that he is continuing where he left off last season, when he hit .211 after the All-Star break compared to .309 before it.
Mattingly was asked if Loney is trying to hit home runs, which have never been his game.
"I hope not," Mattingly said. "Last year, we tried to stay away from that. We always worked on his swing, his approach and understanding what pitchers are trying to do to get him out. We want him to be himself. He's never hit home runs, but he's always around 100 RBIs. To me, that's what we want. We want production, driving in runs."
Mattingly said Blake had healed enough to start at third base, if necessary.