With those six non-roster pitchers all headed to Triple-A Indianapolis, the Pirates are left with 14 pitchers in camp. Two of those relievers, Jose Ascanio and Joel Hanrahan, are expected to begin the season on the disabled list, which essentially leaves the Pirates with 12 arms.
Non-roster relievers Jack Taschner and D.J. Carrasco have not yet been added to the club's 40-man roster, but both will be in the Opening Day 'pen unless the Pirates add any other players before the end of the week. General manager Neal Huntington continues to scour the waiver wire and said he is engaged in trade conversations, so the potential for additional acquisitions certainly remains plausible.
"If there is a trade or a waiver claim, then we'll have to do something," Huntington said. "We're not committing to [Taschner and Carrasco] yet, but they've put themselves in a good position to make the club. We've still got days left and there are still conversations ongoing. Moves could still happen."
Assuming Taschner and Carrasco do stick, they would join a group of four relievers -- Octavio Dotel, Brendan Donnelly, Javier Lopez and Evan Meek -- already considered locks for the bullpen.
Carrasco's versatility makes him a candidate to be used in a variety of relief roles. The right-hander is being stretched out this spring so he can be a multiple-innings option should the Pirates have a rain delay or see their starter get chased early. His role, though, won't solely be in long relief situations.
"He has enough stuff to come in and get somebody out in a leverage situation," Huntington said. "He also has more than enough stuff to pitch later in the game if [manager John Russell] needs him."
Carrasco, who would still love the opportunity to start again at some point, logged 93 1/3 innings for the White Sox last season. He posted a 3.76 ERA in 49 appearances, 28 of which were at least two innings.
Adding Taschner, 31, to the club would give the Pirates a second lefty in the 'pen. He's posted some of the team's best numbers this spring -- two earned runs allowed and 13 strikeouts in 9 2/3 innings -- and has seen his command click after making some changes to his mechanics this offseason.
Taschner's ability to stick with the team all season will depend largely on his ability to get both right-handed and left-handed hitters out. In Taschner's career, right-handed hitters have hit .261 against him compared to the .293 batting average by left-handed batters.
As things sit now, the seventh bullpen opening looks to be Hayden Penn's to lose. Penn, who the Pirates claimed off waivers from the Marlins on Monday, pitched in a Minor League game on Tuesday and is then scheduled to make relief appearances on Thursday and Saturday.
If the Pirates like what they see from the 25-year-old right-hander, the team will most likely stick with a seven-pitcher bullpen and include Penn in it. If Penn doesn't make the cut, Pittsburgh will likely carry six relievers until Hanrahan is ready to return the second week of the season.
Again, keep in mind that all these projections could be voided if the Pirates make any final spring acquisitions.
As for the six pitchers who are now headed to Minor League camp, all will continue to pitch out of the bullpen. Both Karstens and Bass have experience starting, but the Bucs don't really have a need for additional starting depth. By keeping Karstens and Bass pitching out of the bullpen, either could be called up immediately to pitch in relief.
Interestingly enough, the Pirates will open the season with no members from last year's Opening Day bullpen on the club. Three of last year's seven (Sean Burnett, Jesse Chavez and John Grabow) have been traded, one (Matt Capps) was released, two (Craig Hansen and Tyler Yates) are rehabbing injuries and the other (Donnie Veal) will begin the season as a starter in the Minors.
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.