Scahill was recalled from Triple-A Indianapolis on Wednesday.
The Pirates needed another bullpen arm after Tony Watson was placed on the paternity list, so Scahill was called up to fill the void. The 29-year-old struggled a bit during his last stint with the parent club, allowing four runs in six innings of work, but he'll look to ride the momentum of his 2.89 minor league ERA to succeed as a middle reliever in the Pirates bullpen.