Shanahan spoke to reporters via a conference call on Monday, providing injury updates.
"Demo ended up having a rib contusion," Shanahan said. "He should be day-to-day."
Lenoir has been performing at a high level while playing at the nickel cornerback spot. His play against the Cardinals earned him his second-highest Pro Football Focus grade (84.0) of the season. Lenoir was targeted seven times, allowing four receptions for 36 yards and a 71.1 passer rating.
Defensive tackle Kalia Davis left Sunday's game with an ankle injury. Shanahan said he will be "out for a few weeks."
Additionally, wide receiver Jauan Jennings is in the concussion protocol. Defensive lineman Clelin Ferrell is also dealing with an ankle injury and is day-to-day.
Brock Purdy briefly exited the game in the second quarter due to a shoulder stinger. The quarterback remained down on the field after a hit from Cardinals linebacker Dennis Gardeck. After making his way to the sideline, Purdy was examined and cleared to return.
"It was on my left side, so just laid there for a sec, sort of let it calm down and stuff, and then was able to get up, go to the tent, and then from there, I got better," Purdy said. "Literally, as time went on, it just started going away, and that's why I was able to get back in there mid-drive."
It sounds like Purdy won't have any lingering issues from Sunday's game. When asked if there was any residual effect from the injury, Shanahan responded, "Not that I heard. I mean, he felt good last night, and they didn't give me any information today that they're concerned about. So I'm assuming it's your typical stinger, and the fact that he was able to get through the game was a pretty good sign."
Shanahan also provided updates on players who missed Sunday's game. Guard Spencer Burford is expected to return to practice this week. Defensive linemen Arik Armstead and Javon Hargrave, along with tight end Ross Dwelley, running back Elijah Mitchell, and linebacker Oren Burks, are "all in the same boat to where we just got to see how it goes this week with them."
Shanahan added, "So we'll get an idea of that when we start practicing."
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