The Angels' ace takes the mound after allowing a career-high nine earned runs in his last outing against the Rays.
Ervin Santana held the Red Sox to two runs in 6 1/3 innings in the Angels' 5-3 win on Tuesday to open the three-game set, and has been the lone bright spot recently in the rotation, with Zack Greinke, C.J. Wilson and Dan Haren also mired in struggles as the Angels contend for the American League Wild Card.
"You're not waiting and hoping," Angels manager Mike Scioscia said on Tuesday. "You have to balance patience with action. There's not one cure-all for the four guys who have really been struggling."
On the other side, Clay Buchholz takes the mound for the Red Sox looking to build on his strong second half. Buchholz has a 2.03 ERA since the All-Star break, and is 2-0 with a 1.50 ERA in his three August starts.
In his last outing, Buchholz picked up his 11th win of the season by holding the Orioles to three runs over eight innings while striking out seven.
"He brought the competitive spirit to a new level, I thought," Red Sox manager Bobby Valentine said after the outing. "They were jumping on his early pitches. He got down early, and when he saw that we had some resiliency in our offense, he shut the door and shut it quick. He was a great competitor -- a great pitcher tonight."
Angels: Hunter thriving since lineup change
Torii Hunter's move to the No. 2 spot in the Angels' lineup prompted him to shorten his swing, and it has been paying dividends for the 12-year veteran. After moving to the two-hole on June 8, Hunter has raised his average from .238 to .296 in 62 games.
"I cut down my swing as far as swinging hard and trying to go deep like I usually do," Hunter said. "I cut my swing down and try to swing at strikes and take the base hit, and that's why I'm swinging a lot better."
Red Sox: Nava, Padilla back from DL
The Red Sox activated Daniel Nava and Vicente Padilla from the disabled list on Tuesday, with Nava returning to fill the void left in the outfield by Carl Crawford's season-ending Tommy John surgery, while Padilla is back from right arm and groin injuries to give Boston another late-inning arm in the bullpen.
"Supposedly, he's over the hump with the little groin situation that he had, which kind of caused a little triceps-biceps strain," Valentine said of Padilla. "They fixed the bottom, and I think they fixed the top."
Even with Tuesday's loss, the Red Sox have won 10 of their last 15 regular-season games against the Angels at Fenway.
Buchholz is 4-0 with a 2.39 ERA in his four starts against the Angels since 2010.