Jesse Biddle's return to the mound in Reading was cut short on Saturday at FirstEnergy Stadium.
Biddle was removed in the fourth inning of the Fightin Phils game against Binghamton with an injury.
Biddle suffered a strained quad during warm-ups, and is considered day-to-day.
After walking opposing pitcher Daisuke Matsuzaka with the bases loaded, Biddle exited the game with a trainer, limping slightly as he walked off.
Biddle pitched 3.2 innings, allowing two earned runs on four hits, four walks, and four strikeouts.
He suffered the loss in Binghamton's 2-1 win. The B-Mets then won the second game by a 7-3 final.
The Phillies had sent Biddle away from Reading after a June 23 start to give him a mental break.
The left-handed pitching prospect has struggled this year, and admitted he wasn't having fun on the mound.
Earlier this season, Biddle suffered a concussion when he was hit in the head with ice during a hailstorm in Berks County.