Fells left the game in the second quarter and did not return. He had an MRI on Monday morning.
During his news conference Monday afternoon, Cardinals coach Bruce Arians called Fells’ injury a strain and said the results of Fells’ MRI had not come back.
“There’s nothing broken,” Arians said. “But we don’t know the extent of it.”
Fells had one catch for nine yards in Arizona’s 25-13 loss to the Pittsburgh Steelers on Sunday. He dropped his only other target.