After a mediocre year with the Red Sox, John Lackey will undergo Tommy John surgery to repair his elbow that will sideline him for all of the 2012 season.

Lackey disappointed Sox fans in his second year with the team posting a 12-12 record with a 6.41 ERA.

“John Lackey pitched through circumstances this year that I don’t think any of us in this room can fully understand,” Boston’s new GM, Ben Cherington, said Tuesday during a news conference.

News of Lackey’s surgery comes after reports said he drank beer in the clubhouse this past season with fellow starters Josh Beckett and Jon Lester during games they didn’t start. The allegations added fuel to an unhappy fan base following Boston’s September collapse that saw them lose the wild card lead after being up nine-and-a-half games.

Rehab after the reconstructive surgery typically lasts at least 12 months. But it may not be bad news for the club that struggled down the stretch. Change could do this team some good, and if Lackey comes back in top form, Boston could make a run in 2013.