Peralta signed a minor-league contract with the Pirates on Wednesday that includes an invitation to spring training, Robert Murray of FanSided.com reports.
Peralta was reassigned to minor-league camp by the Nationals on Saturday, Mark Zuckerman of MASNSports.com reports.
Peralta gave up three hits and struck out two over three scoreless innings in Thursday's Grapefruit League game against the Mets.
Peralta will be stretched out for a potential starting role in spring training, Jesse Dougherty of The Washington Post reports.
Peralta signed a minor-league contract with the Nationals on Tuesday that includes an invitation to major-league spring training, per Andrew Golden of the Washington Post.
The Tigers granted Peralta his release Monday after clearing waivers.
Peralta was designated for assignment Friday, Cody Stavenhagen of The Athletic reports.
Peralta allowed two runs on three hits in an inning of relief during Sunday's loss to the White Sox. He walked one and struck out two.
The Tigers reinstated Peralta (hamstring) from the 15-day injured list Wednesday.