Running back Antone Smith, who injured his knee in last Sunday's game against the Green Bay Packers, was sidelined for the second consecutive day Thursday. Smith told ESPN.com the injury was related to his patella.
Head coach Mike Smith called Smith's status "day to day" and said the team didn't believe the injury was serious. Smith leads the team with 10 special-teams tackles.
Special-teams coordinator Keith Armstrong discussed the possibility of playing without one of his primary special-teamers.
"We will go with probably one of the backup corners or the backup receivers," Armstrong said. "We have some options. We had some guys on Sunday that went in and actually did a pretty nice job. So, we'll pick from the active roster the guys that we feel give us the best chance to win that down."
Armstrong singled out rookie receiver Darius Johnson as one of the players who filled in after Smith banged up his knee.
Smith was on the field Thursday observing practice but had no helmet. There was no sign of starting safety Thomas DeCoud, who continues to go through concussion protocol after banging his head against the Packers.
If DeCoud is unable to play, rookie Zeke Motta would step in as the starting free safety.