Pirates right-handed pitcher A.J. Burnett (broken orbital bone) will throw a bullpen session Wednesday at Chase Field and will be evaluated by the medical staff and pitching coach Ray Searage. Burnett will fly to Pittsburgh with the team, then make his fourth rehab start Saturday with Double-A Altoona. "One more (rehab) start and then we'll go from there, barring any setbacks," manager Clint Hurdle said. Burnett might make his Pirates debut April 27 in Atlanta. Burnett gave up five runs on seven hits in four innings Monday for Triple-A Indianapolis. He issued four walks and served up two homers, including a solo shot by former Pirates first baseman Brad Eldred.