Peralta was added along with Chris Hatcher and Juan Nicasio to join main lefty J.P. Howell in building a bridge to closer Kenley Jansen, who has since had foot surgery and will miss one to two months of the season.
The health issues of Jansen and Peralta have been followed by recent signings of free agents Dustin McGowan and Chad Gaudin. The pair supplements a large group of competing relievers that includes Brandon League, Pedro Baez, Paco Rodriguez, Adam Liberatore, Daniel Coulombe, Yimi Garcia, David Aardsma, Sergio Santos and David Huff.
Peralta, who turns 39 next month, developed discomfort while working out in the Dominican Republic two weeks before reporting to Spring Training, and he has been limited to playing catch since arriving in Arizona.
Peralta was acquired from Tampa Bay, in large part for his durability. Over the past four seasons for the Rays, he averaged 74 appearances. The only time in Peralta's career spent on the disabled list was last year for a virus.
Peralta suspects his shoulder discomfort is related to the fact that he didn't play winter ball for the first time in a decade. He said the reason he sat out the winter season was to be sure he was healthy for the start of his first Spring Training with the Dodgers and president Andrew Friedman, also Peralta's boss with the Rays.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.