"The production from that spot has not been there either offensively or defensively," said manager Bob Geren. "Now we're going to give somebody else a chance to produce in that spot."
The 29-year old Kouzmanoff hasn't been in the Minors since 2006, but has struggled throughout the season. He's hoping to get himself straightened out at Sacramento, but when asked his thoughts on this move, it's easy to see the veteran got caught off guard.
"Surprise, shock. I didn't see it coming," Kouzmanoff said. "As everybody well knows, I started off slow on both sides of the ball. I was unsatisfied with my play so far this season. I got the news that I'm going down, and all I can do is just go down and get my reps in and keep working and try to work my way back."
Rosales and Sizemore will share duties at third. For Monday's game, Rosales got the start, batting seventh. He had been on the disabled list after missing all of Spring Training with a fractured right foot.
Rosales hit .271 with seven homers and 31 RBIs in 80 games with the A's in 2010.
The A's acquired Sizemore from the Tigers on May 27 in a deal for pitcher David Purcey. He was hitting .267 in nine games at Sacramento, playing most of his games at third base, but Geren said both Rosales and Sizemore can help Oakland at third and in other spots.
Geren said that they will both be given opportunities at third. But Sizemore also can play second while Rosales plays second and short, and both could even be in the lineup at once, giving Cliff Pennington and Mark Ellis some breaks.
De Los Santos made his Major League debut Saturday in Boston. He struck out Jed Lowrie, the only batter he faced.
On Sunday, De Los Santos gave up one run on two hits in two innings and struck out four. Geren said he showed a "good live arm."