"He's pitched in the back of the bullpen, and he's also pitched in the middle," Phillies manager Charlie Manuel said. "I think he has the experience, and our reports are that at the end of the year, he was really throwing good. He definitely fits our bullpen."
The Phillies certainly value the amount of experience Qualls will bring to a relatively young group of relievers, aside from closer Papelbon and 40-year-old right-hander Jose Contreras.
Right-hander Kyle Kendrick is 27. Left-hander Antonio Bastardo and righty David Herndon are a year younger. Michael Stutes is only 25. Then there's the young, talented mix of relievers that includes Justin De Fratus, 24, and Phillippe Aumont, 23.
Given their rotation's ability to eat up innings, the Phillies may carry only 11 relievers. Manuel recently mentioned the possibility of not carrying a second lefty, though there are several candidates for that job, including Dontrelle Willis.
So, who will end up claiming the few available spots in the bullpen?
"I think it's truly the guys who are best capable of filling a role and helping us," Proefrock said. "We have some depth in that area. It's probably the deepest part of the farm system at this point, the arms in the bullpen. It gives us a lot of options."
Qualls figures to be one of those options in the seventh and eighth innings. Manuel said he could see Qualls pitching anywhere given his experience, making him an important piece in the bullpen puzzle.
"He gives Charlie and [pitching coach Rich Dubee] enough flexibility. He's capable of pitching there," Proefrock said. "I think they've got a lot of interchangeable parts. I think that'll play itself out. He's got the experience to pitch basically wherever we need him."
In addition to that versatility, Qualls possesses another attribute that suits what the Phillies believe is one of their strengths: his ability to force ground balls.
With his effective sinker and slider combination, Qualls has induced more than twice as many groundouts than flyouts during his career, and while many advanced metrics may disagree, the Phillies are confident in their ability to turn ground balls into outs.
"I think we have one of the better infield defenses in the game," Proefrock said. "While we've been perceived in the past to be a club that just bangs, the one thing we also do is pitch and catch the ball -- and we always have."
There are plenty of concerns regarding Qualls, however. While he followed up a rough 2010 (7.32 ERA, 1.797 WHIP between the D-backs and Rays) with a respectable 3.51 ERA last season, he struck out a career-low 5.2 batters per nine innings -- down from 7.5 in 2010 and 8.7 in 2008.
There are also his unimpressive career numbers at Citizens Bank Park, where he's allowed opposing hitters to bat .420 with seven homers and a 1.343 OPS in 13 games. Earlier this spring, however, Qualls told reporters those numbers were more a product of facing the Phillies' lineup than the ballpark itself.
And there's the switch from the pitching paradise at San Diego's Petco Park to the tougher pitching environment in Philadelphia. But Proefrock said that wasn't a major consideration when evaluating Qualls, whose best season came while playing in Arizona's more hitter-friendly Chase Field.
"Overall, our guys liked what they saw with their eyes at the end of last year. They thought his stuff was back," Proefrock said. "As far as digging deep into the numbers, I think we're more apt to consider what our guys say, and they saw him a lot toward the end of the year. That's our driving influence in making decisions with those guys."
In the end, the Phillies simply believed Qualls was the right fit for their bullpen. And Manuel would certainly agree.
"He's done everything in the bullpen in his career," Manuel said. "I think our bullpen got better when we got Qualls."