Tomlin will undergo arthroscopic surgery to remove debris in the AC joint of his throwing shoulder next Wednesday, and it will hold him out three-to-four months, Jordan Bastian of MLB.com reports. Tomlin lost out on a rotation spot to begin the season, but would likely have been one of the top candidates to fill a void if an injury occurred. While that could be the case once he returns, that will now be at least midway through the season.