Jennings didn't practice Wednesday due to a hamstring injury, Cam Inman of the San Jose Mercury News reports.
Deebo Samuel (hamstring) also missed practice, leaving Brandon Aiyuk and Ray-Ray McCloud as San Francisco's top healthy wide receivers at the moment. Jennings has caught two or fewer passes in every game since Week 1, but he could see a bit more work if he plays and Samuel sits out Sunday's game against the Rams.