The Phillies are making him a reliever after clearing waivers Sunday and rejoining camp Monday. The club designated Carpenter for assignment last week to make room for right-hander Brian Schlitter on the 40-man roster.
"We'll try to simplify some things," pitching coach Rich Dubee said. "Get him back to a fastball, cutter, split guy. We think he has enough stuff to get through a lineup one time. Getting deeper was maybe a little too difficult."
Carpenter is 1-1 with a 9.31 ERA in five appearances (one start) with the Phillies. He is 45-35 with a 3.71 ERA in 109 appearances (104 starts) in five seasons in the Minor Leagues.
"We feel like this is his best chance to be a productive Major League pitcher," Phils general manager Ruben Amaro Jr. said. "His split might give him a big of an edge as a bullpen guy."