Athletics general manager David Forst revealed Friday that Rooker underwent right forearm extensor surgery Tuesday, Martin Gallegos of MLB.com reports.
Rooker evidently dealt with discomfort in his elbow/forearm for the bulk of the season. It certainly didn't affect his performance at the plate, as he posted a .927 OPS with 39 home runs, but it could be at least part of the reason he didn't start a game in the outfield after May. Rooker is expected to be 100 percent healthy for the start of spring training.