Burnett passed a physical and the commissioner's office signed off on the deal, sources said Sunday.
The Yankees get right-handed reliever Diego Moreno and outfielder Exicardo Cayones from the Pirates in return, sources said. Moreno, a 25-year-old from Venezuela, has split the past two seasons between the Class A and Double-A minor league teams. Cayones, who is 20, spent 2011 in Class A.
The deal had been pending approval from the baseball commissioner's office, which was needed because of the money involved. The Pirates will pay $13 million of the $31.1 million remaining on Burnett's contract, sources said (Burnett is on a year-round contract and already has been paid $1.9 million in 2012).
That approval was not given Friday night -- the deal was finalized too late in the day for that -- and a source involved in the negotiations had told ESPNNewYork.com's Wallace Matthews that official approval from commissioner Bud Selig probably would not come before Monday afternoon or perhaps Tuesday.
As soon as the Burnett deal is done, the Yankees will begin the aggressive pursuit of a veteran designated hitter, sources said.
Sources said there is a good deal of sentiment within the Yankees organization to go after Raul Ibanez -- who wants to play for the team -- to be their designated hitter against right-handers, partly because they believe he can give them some days of outfield play.
Buster Olney is a senior writer for ESPN The Magazine.