But no A's players rank in the American League's top five in position categories or the top 15 outfielders, according to the latest fan vote totals announced Tuesday.
Geren thinks second baseman Adam Kennedy is the most valuable player on the A's roster, but his short time with the team likely has limited his fan support, plus he's not on the ballot.
Oakland acquired Kennedy from Tampa Bay on May 8. He finished this past weekend's series in San Diego with a .304 average, six home runs and 24 RBIs this season.
"He's been kind of that MVP All-Star for our team, but he hasn't been here all year, so that's the difficulty in his candidacy," Geren said. "If you look at the time he's been here, he's worthy of being an All-Star, no doubt."
Kennedy tied his career-high hit total Saturday against the Padres, when he was 4-for-5 with a homer, two RBIs and three runs.
Oakland outfielder Matt Holliday steadily has been considered the most likely A's All-Star candidate. He has hit .269 this season with eight homers, 39 RBIs and 35 runs scored. Holliday also leads the team with eight stolen bases.
Geren said catcher Kurt Suzuki and outfielder Jack Cust also deserve some consideration.
"You know how I feel about Suzuki, and Holliday has great numbers," the manager said. "Cust is leading our team in homers . There are a lot of guys."
Fans can cast their votes for starters up to 25 times with the 2009 All-Star Game Sprint Online Ballot at MLB.com and all 30 club sites until July 2 at 8:59 p.m. PT.
Voting also can be done at the ballpark. At Oakland-Alameda County Coliseum, in-stadium balloting ends Wednesday.
Starting rosters will be announced during the 2009 All-Star Game Selection Show presented by Chevrolet on TBS on July 5. Baseball fans around the world will then be able to select the final player on each team via the 2009 All-Star Game Sprint Final Vote at MLB.com.
And the voting doesn't end there. Fans will have the opportunity to participate in the official voting for the Ted Williams Most Valuable Player Award presented by Chevrolet at the Midsummer Classic via the 2009 All-Star Game Sprint MVP Vote at MLB.com.
The All-Star Game will be televised nationally by FOX and around the world by Major League Baseball International. ESPN Radio will provide exclusive national radio play-by-play, while MLB.com will offer extensive online coverage.