Wellemeyer was sent to minor league camp by the Cubs on Wednesday, and after trying to play catch, found pain in his right hip too severe to continue.
The veteran had an anti-inflammatory shot early in the week to relieve the chronic pain he had in his hip all spring.
"Very disappointing," Wellemeyer said. "I didn't get a single inning here, during the game, where there wasn't a stabbing pain in the hip. I wish I could have gone out there and been healthy. But it is what it is."
Wellemeyer threw 20 pitches in a side session on Tuesday.
A torn right quadriceps muscle last year led to his release in July by the San Francisco Giants. Wellemeyer believes the quad injury may have exascerbated the hip injury this spring.
The 33-year-old pitcher said he'll talk to Chicago-based agent Barry Meister about his future. He may ask for his unconditional release and retire, due to the hip injury.