ARLINGTON -- The A's wanted outfielder Travis Buck to be completely healthy before they brought him back to the big leagues.

Now, they want him to have his swing down, too.

Buck, recovering from shin splints, had struggled during his rehab assignment for Triple-A Sacramento before Friday night when he went 3-for-5 with a home run and four RBIs on Friday night. That upped his average to .238 in his six starts in center field.

That wasn't enough to convince A's management that Buck was ready. Buck's struggles in Sacramento, and an outfield that has played satisfactorily, were enough reason to option him to Sacramento.

"The outfield's doing well so we're going with what we have here," A's manager Bob Geren said. "He needs to get some at-bats to get his swing back."

Buck, in his second season, wasn't hitting when he was placed on the disabled list on April 24. He was batting .154, the lowest average in the American League at the time. He had only six RBIs and had 20 strikeouts in 65 at-bats.

Meanwhile, Emil Brown, who has taken Buck's place in right field, was second in the AL with 29 RBIs going into Saturday's game against the Rangers. Brown, who is batting .274, has eight go-ahead RBIs, second to Boston's Manny Ramirez. He had three go-ahead RBIs in the series against Baltimore earlier this week.

Geren also has been pleased with the rest of the outfield rotation of Ryan Sweeney and Rajai Davis in center field and Jack Cust in left field. Sweeney and Davis have combined to hit .284. Cust leads the team with four home runs.

Buck, who has never started more than seven consecutive games, has been plagued with injuries during his short career. The 23-year-old was limited to 82 games last year, but he still batted .288 with seven home runs and 34 RBIs.