Santana (arm) struck out two over two scoreless innings of relief in Saturday's 5-2 loss to the Mets. He gave up two hits and no walks.
The Pirates claimed Santana off waivers from the Yankees on Tuesday.
The Yankees designated Santana for assignment on Sunday.
Santana allowed one hit in one scoreless inning to earn the save during Sunday's 5-2 win over the Tigers. He struck out two.
The Yankees selected Santana's contract from Triple-A Scranton/Wilkes-Barre on Friday.
The Yankees reassigned Santana to minor-league camp Monday, Bryan Hoch of MLB.com reports.
Santana is "in the mix" for a spot in the Yankees' Opening Day bullpen, Max Goodman of The Newark Star-Ledger reports.
Santana signed a minor-league contract with the Yankees on Wednesday, Jessica Kleinschmidt of The Comeback reports.
The Mets designated Santana for assignment Saturday.
The Mets selected Santana's contract from Triple-A Syracuse on Wednesday, Abbey Mastracco of the New York Daily News reports.