SANTA CLARA -- Tight end Vernon Davis is scheduled Saturday to undergo a contact simulation, the final step in the NFL's concussion protocol before the 49ers will allow him to return to action.
When asked Friday if Davis is on course to return to action Sunday against the Arizona Cardinals, 49ers head coach Jim Harbaugh said, "He's on course, yes."
After going through his second limited practice of the week, Davis said he was not certain whether he will play Sunday.
"I feel all right," said Davis, who is listed as questionable on the team's official injury for the 49ers' season finale.
Does he feel 100 percent?
"I'm all right," Davis answered.
Davis sustained a concussion on a big hit from Seattle Seahawks safety Kam Chancellor in the first quarter of the 49ers' 42-13 loss on Sunday night. Davis left the game and did not return.
Chancellor was penalized 15 yards for unnecessary roughness. But the league did not fine him for an illegal hit. Davis said he thought the hit was helmet-to-helmet, but he did not want to re-watch it.
"I don't think it was legal," Davis said. "I saw it on the news, but I didn't really go in and look at it. I didn't want to see it."
Harbaugh said 49ers team doctors will make the ultimate call on whether Davis plays Sunday. Is the priority on being ready for the playoffs?
"I'm thinking I got to be ready for this game," Davis said. "That's how I'm approaching it. I don't like sitting back and watching if I can get out there and help my teammates."
Defensive tackle Justin Smith remains out -- officially listed as "doubtful" -- with a partially torn triceps tendon in his left arm. Smith runs the risk of causing more damage to his arm if he tries to return for the playoffs, Harbaugh confirmed.
"Yes, I think there's a higher risk," Harbaugh said. "It's something he'll have to have repaired, surgically repaired, at the end of the season either way."
With Smith out for Sunday's game and defensive tackle Will Tukuafu questionable with a neck injury, the 49ers expect immediate contributions from defensive lineman Tony Jerod-Eddie, who was promoted from the practice squad on Friday.
Out: WR Mario Manningham (knee) -- placed on injured reserve
Doubtful: DT Justin Smith (elbow, triceps)
Questionable: TE Vernon Davis (concussion), LB Clark Haggans (shoulder), DT Will Tukuafu (neck)
Probable: LB Navorro Bowman (wrist, shoulder), LB Ahmad Brooks (shoulder), CB Tarell Brown (shoulder, knee), LB Tavares Gooden (illness, rib), C Jonathan Goodwin (illness), RB Frank Gore (knee), G Mike Iupati (shoulder), P Andy Lee (illness), RB Bruce Miller (shoulder), S Trenton Robinson (finger), CB Carlos Rogers (knee, toe), LB Aldon Smith (shoulder), S Donte Whitner (knee)
Questionable: WR Early Doucet (concussion)
Doubtful: WR Laron Byrd (knee)
Questionable: G Mike Gibson (calf), T Nate Potter (ankle), RB Anthony Sherman (knee), DE Ronald Talley (ankle)
Probable: S Rashad Johnson (hamstring), S Kerry Rhodes (illness), S James Sanders (calf), CB Gregory Toler (hamstring), DT Dan Williams (hamstring), S Adrian Wilson (illness)