ATLANTA -- Braves left-hander Mike Minor will miss the rest of the season after shoulder surgery.

The team announced Thursday that Minor underwent surgery the previous day in Los Angeles to repair the labrum in his left shoulder. He is expected to return for the start of spring training next year.

Minor had not pitched this season. The 27-year-old was sidelined after experiencing soreness in spring training and went on the disabled list April 5 with what was described as shoulder inflammation.

When the injury didn't improve, Minor was moved to the 60-day DL.

Once viewed as a key member of the Braves' young rotation, Minor was bothered by shoulder problems several times last season. He slumped to 6-12 with a 4.77 ERA in 25 starts.

A former first-round pick, Minor went 11-10 in 2012 and followed up by going 13-9 with a 3.21 ERA in 32 starts for a team that won the East Division.

But this latest injury raises doubts about his future in Atlanta. Minor is making $5.6 million this season and, given his injury woes, the Braves could decide not to tender him a contract for 2016 rather than facing arbitration, making him a free agent.

With Minor on the sideline, the Braves' rotation has struggled this season. Julio Teheran and Alex Wood are off to slow starts, Eric Stults (1-4, 5.36 ERA) hasn't been effective and Trevor Cahill (0-3, 8.15) was quickly replaced by top prospect Mike Foltynewicz. Newcomer Shelby Miller (4-1, 1.60 ERA) has been the only effective starter.