Donnelly, who hasn't pitched since April 27, will join Evan Meek and Joel Hanrahan in the back end of a Pirates bullpen that has held its own in Donnelly's absence. His availability, too, will allow Russell to lighten the load on Meek and Hanrahan, who have been the primary go-to relievers in the seventh and eighth.
"You aren't going to be able to use Meek and Hanrahan every night," Russell said. "It covers us for more days in a row. It takes a lot of pressure off those last two or three innings to get to [closer Octavio] Dotel."
Donnelly made 11 appearances before a left oblique strain sidelined him for three weeks. He was scored upon in just two of those games, both of which were already out of hand when Donnelly entered.
The Pirates will have to make a corresponding roster move on Thursday to open up a spot for Donnelly. Jeff Karstens could become the odd man out of the bullpen, or if Brian Burres struggles in his start on Wednesday night, he might find himself out of the rotation.
-- Jenifer Langosch