PITTSBURGH -- Pirates pitcher A.J. Burnett will undergo surgery on Friday to repair a fractured right orbital bone.

The right-hander injured himself on Wednesday at the team’s spring training facilities in Bradenton after a bunt attempt caromed off his face. He flew to Pittsburgh late Wednesday to be further evaluated.

There is no immediate timetable for Burnett’s return. The 35-year-old was acquired in a three-player trade with the New York Yankees last month and was expected to be the No. 1 starter on a team looking to improve on a 72-90 record last season.

Burnett, a two-time World Series winner, is also trying to rehabilitate his career. He struggled during his final two seasons in New York, posting a 21-26 record with a 5.20 ERA. He led the major leagues with 25 wild pitches in 2011 while allowing a career-high 31 homers.