Jennings (hip) isn't taking part in Thursday's practice, David Lombardi of The San Francisco Standard reports.
Meanwhile, fellow WR Deebo Samuel (wrist) was on the field Thursday but donning a blue non-contact jersey, per Nick Wagoner of ESPN.com, indicating he'll go down as a limited participant for a second straight session. Jennings may be in danger of sitting out Sunday against the Chiefs, with Friday's injury report potentially providing some clarity on the situation ahead of the weekend.