Qualls had nine consecutive scoreless appearances before surrendering three runs over one inning to the Pittsburgh Pirates on Wednesday night. He has pitched 31.1 innings this season for the Phillies with a 4.60 ERA and 19 strikeouts. Over his nine-year career, Qualls has appeared in 572 games with a 3.82 ERA. He bounced back from a horrendous 2010 season (7.32 ERA combined with the Arizona Diamondbacks and Tampa Bay Rays) to post a 3.51 ERA with the San Diego Padres last year.
Horst is a 26-year old reliever whose only prior MLB experience came with the Cincinnati Reds last season, when he amassed a 2.93 ERA over 12 appearances. Horst has a 2.11 ERA through 26 appearances with the Lehigh Valley IronPigs this season.