Manager Clint Hurdle said Erik Bedard will start Opening Day on Thursday, April 5 against the Philadelphia Phillies.
The announcement was made following the Pirates' 8-6 loss to the Tampa Bay Rays.
Jeff Karstens and James McDonald follow Bedard, and Kevin Correia, last year's Opening Day starter, takes the mound April 10 for the team's first road game against the Los Angeles Dodgers.
"We felt our strongest rotation coming out of the chute would fall this way," Hurdle said.
Bedard is 0-1 with a 6.23 ERA in three starts this spring. He has made two Opening Day starts, with the last coming in 2008 for the Seattle Mariners.
"He's done this before," Hurdle said.
Bedard takes the place of A.J. Burnett, who underwent surgery earlier this month to repair a fractured orbital bone. Burnett has thrown two bullpen sessions since the surgery and is expected back some time in May or June.
"We were planning on giving the ball to A.J. to start the season," Hurdle said.
The Pirates have not made a decision on a fifth starter, Hurdle said. The Pirates, who have three off days in April, may not need a fifth starter until May.