As many on AN have speculated, given Brett Anderson's visible loss in velocity and struggles to get opposing hitters out over the last several starts, the pitcher's left elbow is going to be examined by doctors (just our team's or external, not quite clear yet) and he has already left the team, headed back to the Bay Area. If he does land on the DL, this will see him joining hurlers Dallas Braden, Brandon McCarthy and Tyson Ross just in the last two months (and we're not even counting Rich Harden) - another blow to the A's otherwise excellent staff.
Anderson's last outing, which lasted only five innings, and saw him give up five runs to the Red Sox, brought his season ERA to a not-so-shiny 4.00, and dropped his record to 3-6.
Source for today's bad news comes courtesy of the Contra Costa Times.
UPDATE: Susan Slusser reports that Rosales has been called up and is in tonight's lineup. De Los Santos and Kevin Kousmannoff have been "optioned out". Scott Sizemore has also been called up. (via Twitter)