With Mark Ellis coming off the disabled list and returning to second base, Kennedy is expected to see regular playing time as the starting third baseman. He'll also play first, and has experience as a big league outfielder.
"[Jack] Hannahan has done a great job at third," Kennedy said. "It's going to be tough to replace that."
Kennedy got a brief taste of the position Saturday, shifting from second to third in the eighth inning of Oakland's 11-9 loss to Colorado.
Only one ball went Kennedy's way -- a scorching shot with some topspin hit by Garrett Atkins that got by for a base knock.
"There was nothing funny about that," Kennedy joked.
Troy Tulowitzki tested Kennedy early on Sunday, dropping down a bunt to lead off the second. Kennedy did his part, bare-handing the ball and delivering an accurate throw to first, but couldn't gun down the speedy shortstop.
In the seventh, Kennedy caught a towering popup by Clint Barmes in foul territory. He then snared a Tulowitzki liner and threw out Chris Iannetta on a routine ground ball in the eighth.
"He looked comfortable," manager Bob Geren said. "He made a nice play on that bunt -- proper footwork, reacted well. I thought he looked good."
Oakland optioned Daric Barton to Triple-A Sacramento to make room for Ellis on the roster. Barton went 2-for-17 (.118 average) in 12 games with the A's. He doubled, walked and scored two runs in two plate appearances Saturday after coming off the bench.
Ellis batted .162 with a double and three RBIs in 10 rehab starts between Sacramento and high Class A Stockton. He was batting .206 through 18 games with the A's prior to landing on the DL.
"Getting Mark back is big for us," Kennedy said. "He's a great defender and he can swing the bat. ... He knows how to play the game."
Adam Loberstein is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.