The Seattle Seahawks have promoted quarterback Sean Mannion to their roster for Sunday's Week 14 game with the San Francisco 49ers, with that move a clear sign Geno Smith will not be available to play.

Starting quarterback Smith did not practice on Friday and was listed as questionable with a groin injury.

They signed Mannion to the practice squad as insurance, and the former Vikings quarterback appears poised to back up Drew Lock in what would be a first start as a Seahawk for the former second-round pick of the Denver Broncos.

Lock filled in for Smith during the second half of their defeat to the Los Angeles Rams in Week 11. Smith suffered a bruised triceps muscle in that game but returned for the Seahawks' final offensive series after Lock converted just two of his six pass attempts for three yards and an interception.

When asked about Smith's potential availability for Week 14, head coach Pete Carroll said on Friday: "We'll see. We rested him today."

But he was bullish on Lock, saying: "He's been waiting for this opportunity, looking forward to it and preparing for it. If this comes to pass, then he is as ready as he can get."

That opportunity appears increasingly likely to come and, with the Seahawks looking to arrest a three-game losing streak that has dropped them out of the playoff spots, it is one Lock cannot afford to waste.

Seahawks face nervous wait over Geno Smith for must-win game

Pete Carroll gave little away.