However, if Spring Training performances are any indicator of how the bullpen will fare this season, maybe it's time to eliminate some of those concerns.
"Coming into spring, I don't think people thought we'd have a hard decision, but it's come down to that," manager John Russell said. "There's not much time left, but these guys have made it awfully hard on us. The decisions will be tough, but that's what you like."
At the start of the camp, closer Matt Capps and setup men Damaso Marte and John Grabow were the only ones guaranteed a spot on the Major League club. That left a number of organizational prospects and non-roster invitees ready to compete for the final four spots.
That competition has produced some surprises, and as a result, dictated some tough decisions be made by management this week concerning the makeup of their relief corps on Opening Day.
So here's how things stand going into the last week, as the Pirates have 12 extra pitchers still left in camp with four bullpen openings still up for grabs:
Virtual lock: It's hard to imagine a scenario in which Franquelis Osoria won't be on the Opening Day roster. The Pirates need at least one more right-hander in the bullpen and Osoria appears to be that guy.
He came into camp as the leading candidate for the right-handed setup job and has done nothing but further solidify it over the past month. Heading into Monday's game, Osoria has made five scoreless spring appearances.
"What he's doing is very encouraging and he's making a very good impression," pitching coach Jeff Andrews said. "He's aggressive. He's confident. He's got a lot of things to offer."
Still in the mix: Based on spring performance, it would be hard to find a more worthy candidate for the bullpen than lefty Sean Burnett. The former first-round pick, who shifted focus from starting to relieving at the beginning of Spring Training, has not allowed a hit in any of his last eight appearances.
Assuming that Russell is comfortable with three -- and potentially four -- lefties in the bullpen, Burnett has to be under strong consideration.
Then there is Byung-Hyun Kim, whom the Pirates signed during the second week of camp, to consider.
General manager Neal Huntington reiterated at the time that Kim would not be guaranteed a spot on the team despite being signed to a Major League contract. Since his results have not been overwhelming up to this point, it's still up in the air as to whether he has a future in Pittsburgh. If the Pirates decide not to keep him, they will still owe him $300,000 on his contract.
Deciding whether to give a roster spot to Rule 5 Draft pick Evan Meek could prove to be the most tantalizing decision for management. The Pirates have been intrigued by Meek's power arm, but knowing that the right-hander has not pitched above Double-A before may be a concern.
If the Pirates want to ensure that Meek stays in the organization, he'll have to spend the entire season with the Major League team. Otherwise, the Pirates must offer Meek back to Tampa Bay, which can buy back his rights for $25,000.
When it comes to adding a long reliever, lefty Phil Dumatrait and right-hander Jaret Wright are assumed to be the two strongest candidates. Dumatrait is out of options on his contract and Wright has an escape clause in his, meaning that if the Pirates don't take both, they risk losing either to other teams.
Both have been impressive at times this spring and have made legitimate arguments for being on the team next Monday. Wright hasn't allowed a run in any of his last three starts, while Dumatrait's only notable hiccup came on March 9 against the Tigers.
However, it's most likely that only one will be with the team in a week ,and the fact that Dumatrait is just 26 years old and could be under the Pirates' control for years may be reason enough for the Pirates not to want to let him go.
Long shots: Hector Carrasco, Masumi Kuwata, Casey Fossum, Jonah Bayliss and Elmer Dessens are probably best put in this category.
If the Pirates decide to go with one of the veterans that they signed to Minor League contracts during the offseason, Carrasco would most likely be the choice, as he hasn't allowed a run since his first Spring Training outing. However, the Pirates may have too many other candidates in line before Carrasco.
Dessens got a late start this spring after experiencing soreness in his lower back and has made just two one-inning appearances since. Kuwata has been impressive, allowing just one run in five starts, but doesn't appear to be in the mix for one of the final spots.
Bayliss didn't prove he was Major League-ready during his time with the Pirates last season and hasn't done anything dazzling this spring to catapult himself into serious contention for a bullpen spot.
And then there is Fossum, who has had up and down results this spring in what he hoped would be a much-needed fresh and healthy start. He'd be another candidate for the Pirates to consider calling up as either a starter or reliever down the road. But a start in the Majors doesn't appear to be in the cards.
Out of the running: Though he's still in big league camp, lefty Juan Perez has been shut down from pitching for the time being after tearing a ligament in his left elbow in a March 7 appearance. As of now, Perez is not slated to have surgery, but will start the season on the disabled list.
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.