From Chronicle Staff Writer Susan Slusser in Baltimore

See more UPDATES (including Kevin Kouzmanoff being optioned) below the Anderson material.

Several sources have confirmed that Brett Anderson was to return to the Bay Area today to get his left elbow checked, and according to one source, Anderson had expressed concern that he might need Tommy John surgery if the ulnar collateral ligament is torn.

Anderson was on the DL twice last year with left elbow inflammation last year, and there was some worry around the team at the time that perhaps he had a ligament tear, but he was not diagnosed with any structural damage at the time and he pitched well when he came back, with a 2.98 ERA the rest of the way; he was particularly good in September, when he went 3-1 with a 2.23 ERA.

Anderson has seen a dip in his velocity recently, and he said Sunday after allowing five runs (all the product of just two home runs) that he was more concerned about the 3-4 mph dip on his slider and the fact that his slider, his best pitch, was not as sharp as usual.

The A’s already have had numerous starters go on the DL, including two members of the Opening Day rotation, left-hander Dallas Braden (shoulder surgery) and right-hander Brandon McCarthy (stress reaction, right shoulder, an injury he has had in previous years). Right-hander Rich Harden opened the season on the DL with a muscle strain under his right arm, and right-hander Tyson Ross is on the DL with an oblique strain. Only Braden’s injury is season-ending.

Should Anderson miss a start or potentially more, left-hander Bobby Cramer would be likely to fill in, at least until Ross, McCarthy or Harden is able to return from the DL.

As recently as May 26, Anderson threw eight shutout innings against the Angels, allowing three hits, and he had a 2.84 overall ERA at that point. In his past two starts, he has allowed 14 earned runs in 10 1/3 innings. In his May 31 start, the 23-year-old gave up 10 runs, nine earned, and remained in to throw 5 1/3 innings and 103 pitches. He also threw 103 pitches on Sunday at Boston, which is right around or even a little under the norm for A’s starters this time of year.

Other UPDATES

3B Kevin Kouzmanoff has been sent down to Sacramento, as has P Fautino De Los Santos. Adam Rosales is in the starting lineup at third. And recently acquired IF Scott Sizemore has been brought up from Sacramento.

The lineup: Crisp CF, Barton 1B, Jackson LF, Willingham DH, Suzuki C, Ellis 2B, Rosales 3B, Sweeney RF, Pennington SS, Gonzalez P