As is common practice with any player dealing with concussions, there was no definitive update about 24 hours after St. Louis Rams running back Zac Stacy, cornerback Trumaine Johnson and left guard Chris Williams suffered head injuries Sunday against the Chicago Bears.

The NFL long ago put in place proper protocol on how to deal with concussions and part of the protocol requires players suffering from concussions to pass a series of a tests before they can be cleared to return to the field. That means the status of the three key starters the Rams lost to head injuries Sunday will remain unknown for at least a few more days.

Rams coach Jeff Fisher said Monday afternoon that all three players would be monitored this week before any determination is made on their availability for this week's game against San Francisco.

"We have a series of things that we do today, tomorrow and Wednesday," Fisher said. "Right now everybody is doing fine."

Benny Cunningham replaced Stacy against the Bears and would be the odds-on favorite to do so again should Stacy be unable to get clearance to return. The same applies for Shelley Smith in Williams' stead.