Parkinson did not participate in Wednesday's practice due to a rib injury, Adam Grosbard of The Orange County Register reports.
Parkinson may have picked up the injury during the Rams' 35-21 win over the Raiders in Week 7, when he caught five of six targets for 48 yards. He'll have two more opportunities to practice in at least a limited capacity ahead of Sunday's game against the Chargers. Terrance Ferguson (ankle) will remain on IR for Week 8, so if Parkinson cannot play, then Tyler Higbee and Davis Allen would serve as the Rams' top tight ends.