The switch allows the A's to break up their lefties -- Friday starter Jon Lester and Kazmir -- while also giving Kazmir extra rest. Kazmir, who will pitch on six days' rest, has already pitched 158 innings, equaling his total from last year.
He hasn't thrown more than that since compiling 206 2/3 innings with the Rays in 2007.
"Just giving Kaz a little bit more time, and then splitting the lefties up," said manager Bob Melvin. "We've been looking for a way to do that for a little while, so it's two-fold."
Melvin did not suggest Kazmir is tired but pointed to the luxury of being afforded the chance to lend him extra time off as his innings climb.
"Just when you think he maybe looks a little tired, then he goes out and pitches a great game," he said. "He's been really consistent for us, but it's been a while since he's pitched the innings that he's pitched this year. Shark feels really good right now, so it just gave us an opportunity to give Kaz an extra day or two."
Kazmir has had a tough time in two starts against his former Angels team since Los Angeles released him in 2011, lasting just three innings on both occasions. He most recently allowed the Halos seven runs on 10 hits in Sunday's loss.