Athletics' Daulton Jefferies: Requires surgery

Jefferies will undergo surgery to address his thoracic outlet syndrome, Matt Kawahara of the San Francisco Chronicle reports.

Jefferies received a second opinion Tuesday after being diagnosed with thoracic outlet syndrome, and he'll ultimately require a procedure. The Athletics won't provide an update on the right-hander's status until after he undergoes surgery Monday, but the procedure often carries a recovery timetable of several months. While it's possible that Jefferies will be cleared for game action in the final few weeks of the season, it wouldn't be surprising to see the team exercise caution with his rehab process since Oakland is unlikely to be in playoff contention late in the year.