"We're facing a young kid who has good stuff," manager Bruce Bochy said. "He's been throwing the ball really well, so we expect to see a good pitcher out there."
McCarthy is sidelined with ongoing shoulder soreness, giving way to Griffin, who was called up from Triple-A Sacramento. Bochy said the team relied on scouting reports and game film to prepare for Griffin, who wasn't announced as the A's starter until a few hours before the game.
"You try and get all the information you can," Bochy said. "He's a tall kid with good stuff, four pitches. We pretty much know what he has; we've just never seen him."
Griffin held a 3-2 record and 2.81 ERA in Sacramento, including three starts against the Fresno Grizzlies, the Giants' Triple-A team. Justin Christian joined the Giants from Fresno on June 15, and Bochy said the outfielder helped Giants better prepare to face Griffin.
"That's the difference in the game," Bochy said of the Giants preparing to face Griffin. "With video, our advance scouts, we're able to get all this information, but what it comes down to is that they have to throw it over the plate and you have to hit it. Sometimes you put too much into not having enough on the kid."