The Athletics released Guerra on Aug. 5.

The A's declined to tender Guerra a contract for 2023.

Guerra underwent reconstructive surgery on the UCL in his right elbow Wednesday, Matt Kawahara of the San Francisco Chronicle reports.

Guerra will undergo elbow surgery on April 13, Matt Kawahara of the San Francisco Chronicle reports.

Guerra (forearm) will undergo surgery that will force him to begin the season on the injured list, Martin Gallegos of MLB.com reports.

Manager Mark Kotsay said Thursday that Guerra (forearm) will receive a second opinion, Matt Kawahara of the San Francisco Chronicle reports.

Guerra is considered day-to-day after he experienced forearm tightness coming out of his Cactus League debut Wednesday, Matt Kawahara of the San Francisco Chronicle reports.

Guerra and the Athletics agreed to a one-year, $815K deal Tuesday, Ken Rosenthal of The Athletic reports.

Guerra fired 1.2 scoreless innings in a loss to the Yankees on Friday, allowing a hit and recording a strikeout.

Guerra has seven scoreless appearances spanning 6.2 innings, a stretch during which he's allowed four hits and generated a 7:1 K:BB and one hold.