The 47-year-old Moyer is the oldest pitcher in the major leagues. He threw 18 pitches in the first inning Tuesday night, allowing two-out hits to Albert Pujols and Matt Holliday before getting Allen Craig on a lineout.
Andrew Carpenter, recalled from Triple-A Lehigh Valley earlier Tuesday, replaced Moyer in the second inning.
Moyer almost certainly is headed for the 15-day disabled list. The Phillies have lost five of six since the All-Star break and demoted another starter earlier in the day, sending Kyle Kendrick to Triple-A Lehigh Valley.
The door to manager Charlie Manuel's office was closed for more than a half-hour after the game while the Phillies discussed their options. One of them would be recalling Kendrick, and Manuel said the team was waiting for minor league affiliates to check in.
"We were talking about things we wanted to do," Manuel said. "We've got a plan. It will work its way out."
Moyer said he expected to pitch again this season.
"When that is, I have no idea," Moyer said. "My goal is to keep a positive mental outlook whatever the diagnosis is."
Information from The Associated Press was used in this report.