San Francisco 49ers head coach Kyle Shanahan jumped on a conference call with reporters on Tuesday and shared some injury updates as the team heads into its third preseason game, a road matchup against the Kansas City Chiefs.

Wednesday will be day 17 since running back Jerick McKinnon (knee) received his platelet-rich plasma (PRP) procedure. Shanahan doesn't anticipate him practicing on Wednesday, but he could be limited on Thursday.

"With it being a short week and the practices we have, I don't think we will do it tomorrow," Shanahan said. "Maybe the day after, we'll start putting him into individual and stuff, but I don't think he's going to be able to do team drills and stuff this week."

The 49ers fear the worst for rookie wide receiver Shawn Poindexter, who left Monday night's game against the Denver Broncos with a knee injury. Shanahan believes he suffered a torn ACL, but it hasn't been confirmed yet.

It was reported earlier on Tuesday that the 49ers were re-signing wide receiver Chris Thompson. Shanahan notes that won't happen until they get the definitive word on Poindexter's condition.

"Poindexter still has to get his X-rays and everything," Shanahan said. "We were expecting the worst with the ACL, but we haven't got it confirmed yet. When we do, we plan on making that move with Chris Thompson."