SANTA CLARA -- With their depth already tested, the 49ers could be without their best offensive player Sunday for a key NFC West matchup.
Tight end George Kittle was listed as questionable on Friday with a calf injury, as the 49ers continued preparations to face the Seattle Seahawks in Week 4 at Levi's Stadium. Kittle was seen conditioning prior to practice with straight-line running on a side field.
Coach Kyle Shanahan said the fact Kittle was able to do some running makes him more encouraged for his availability for the game. He went through limited practice on Friday.
Running back Trey Sermon appears in line to get his second consecutive start. He rushed for 31 yards and a touchdown in 10 carries against the Green Bay Packers in Week 3.
The 49ers figure to be without veteran cornerback Josh Norman, who sustained a bruised lung and spit up blood during the team's game against Green Bay.
Veteran Dre Kirkpatrick and rookie Deommodore Lenoir are the candidates to replace Norman at the cornerback position opposite Emmanuel Moseley.
Nickelback K'Waun Williams (calf) was ruled out. He is expected to be out of action for several weeks. The 49ers will decide among newly signed Buster Skrine, Lenoir and Dontae Johnson to replace Williams.
In seven career games against the Seahawks, Kittle has 28 receptions for 341 yards and no touchdowns. He ranks second on the team behind Deebo Samuel with 15 catches for 187 yards.
For the Seahawks, wide receiver Tyler Lockett is questionable.