Worley was 9-4 with a 3.20 ERA in 19 starts for Reading this season. The 22-year-old has pitched 17 consecutive scoreless innings in his past two outings and was recently named the Phillies' Minor League Pitcher of the Week.
The 25-year-old Carpenter was called up on Tuesday and gave up three runs in three innings to the Cardinals during his only appearance of the season.
With Kyle Kendrick optioned and Jamie Moyer likely to land on the disabled list, the Phillies need a starting pitcher for Saturday and Sunday.
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.