Dr. Keith Meister will read Scheppers' MRI and evaluate Tanner Saturday morning.
Scheppers, who allowed four runs on five hits and two walks in two-thirds of an inning on Thursday against the Cubs in Mesa, later complained of the back problem. He was scheduled to pitch three innings.
"It's still pretty sore," Scheppers said Friday morning.
The club has high hopes for Scheppers. He began the 2010 season pitching in relief in Double-A, and was promoted to Triple-A after 11 innings. He posted a 1.13 ERA over his first seven appearances out of the bullpen in Oklahoma City.
"I went out there and I wasn't feeling the greatest, and on my third pitch, I felt something in my back," Scheppers said. "I tried to pitch through it, and it might not have been the smartest idea. I'm trying to get healthy and we'll see what happens."