Jennings (hamstring) was a non-participant at Thursday's practice, David Lombardi of The Athletic reports.
Jennings was listed the same way Wednesday, but he at least was seen running on a side field in a helmet and uniform Thursday, according to Matt Barrows of The Athletic. The 49ers' No. 1 wide receiver Deebo Samuel (hamstring) also hasn't practiced this week, so the team's situation at the position bears watching to see if either player may suit up Sunday at the Rams.