The acquisition of Tyler Yates via a trade with Atlanta last week helped define those roles. And while it had been hypothesized that Yates would be the Pirates' go-to right-hander late in games, it wasn't until Monday that manager John Russell strongly suggested that he intended to slot Yates into that spot.
"He's the type of guy that has the presence and the type of stuff to pitch later in the game, and we'll use him accordingly," Russell said. "He very much complements [John] Grabow and [Damaso] Marte to get to [Matt] Capps. As of now, that's how we envision using him."
Russell has seen just one inning from Yates, that coming last Friday in one of the Pirates' final Grapefruit League games. Yates threw one scoreless inning.
"I'm always eager to be one of the main guys in the bullpen," Yates said. "I think I can handle it. I don't think they would have gone out and gotten me if they didn't think I could."
Having Yates will help take some of the late-inning workload off of Marte and Grabow. While Marte is a specialist at getting left-handed hitters out, Russell has said he won't necessarily limit his workload only to lefty-lefty matchups. But having Yates will at least minimize the situations in which that is necessary.
With Yates set to assume late-inning duties, Russell now has the flexibility to use Franquelis Osoria in a more situational role.
"He is the wild card in the bullpen," Russell said.
With an often devastating sinkerball pitch, Osoria would be a prime candidate to come in if the Pirates were in need of a double-play ball. His ability warm up quickly -- as quickly as within the span of one batter, noted Russell -- will also be an asset.
Phil Dumatrait has already been slotted in as the long reliever out of the 'pen, leaving Rule 5 Draft pick Evan Meek as the final piece. Russell said he will find less pressured situations where Meek can have some initial success. But until that time comes, Meek, too, is going to have to step up.
"When you have a seven-man bullpen, you're not just going to be able to hide him," Russell said. "He's going to have to do his job. He's going to have to pitch. There are ways that you can take some of the workload off of him along the way, but he's going to have to pitch. In order for us to be successful, we need all seven."
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.