OAKLAND -- A's rookie Eric Patterson, who left Wednesday night's game against the Angels in the fifth inning after straining his right hamstring on the basepaths, likely won't return to action in 2008.

"They said it's seven to 10 days," Oakland manager Bob Geren said Thursday before the finale of a three-game series at McAfee Coliseum. "So he's ... pretty much out [for the year.]"

Patterson, one of the four players acquired in the July trade that sent Rich Harden and Chad Gaudin to the Cubs, was mired in a 2-for-21 (.095) slump when he pulled up after rounding second base Tuesday night. He was immediately replaced.

Named the second baseman on the Pacific Coast League's postseason All-Star team, Patterson, 25, also has played in left field during his two stints with the A's since the trade. He's batting .174 with a .269 on-base percentage in 92 at-bats over 30 games with Oakland, and if the A's lose free-agent-to-be Mark Ellis, Patterson will be among the candidates to take over at second base.

"He got almost 100 at-bats; that's pretty good," Geren said. "We'll see more of him in the spring."