"When you're thinking of what could have been some really bad (stuff), we can take care of this and move on," Carpenter said (St. Louis Post-Dispatch).
Carpenter's throwing program has yet to be determined, but pitching coach Derek Lilliquist said the right-hander can break camp with the club if he faces hitters by March 20.
Carpenter, 36, told the Post-Dispatch that his issue is "waves of weird pain I had never experienced before." He said he was not concerned about making the opening-day roster.
Carpenter was 11-9 with a 3.45 ERA, 1.26 WHIP and 191 strikeouts in 237 1/3 innings last season. He made six postseason starts, including three in the World Series, where he went 2-0 with a 2.84 ERA and won the decisive Game 7.