Seattle Seahawks head coach Pete Carroll "cannot fathom" playing without wide receiver Tyler Lockett after he suffered a broken index finger.

Lockett sustained the injury on the final offensive drive of the Seahawks' 21-13 loss to the San Francisco 49ers on Thursday.

The win clinched the NFC West for 10-4 San Francisco and served as a further dent to Seattle's hopes of securing a Wild Card berth at 7-7.

Seattle's prospects of reaching the postseason now appear to be further diminished by the loss of the former first-team All-Pro and two-time second-team All-Pro Lockett.

The Seahawks are still deciding how to treat the injury, with surgery an option for Lockett, who could return in two weeks, according to Carroll.

"There's a couple different ways that they can do the surgery," Carroll said. "One of the ways gives him a chance to be back.

"Remember [running back] Rashaad Penny... had an injury similar, very similar.

"So they've already floated that thought and they're going to talk about all the options and all that and we're going to love him up and take care of him. Whatever the right thing to do to take care of him, we're going to do.

"I can't fathom playing without Tyler. I got a chance to hang with him, just to try to express what it's like to be working with a guy like this for so long.

"He's such an incredible player. He's not in tremendous pain. He's got a broken hand.

"You feel sorry for him, but he's such a magnificent football player and a member of the team and member of the community and our area and our fans ... that we're gonna miss the heck out of him for whatever he misses."

Since entering the NFL as a third-round pick in 2015, Lockett has racked up 7,031 receiving yards and 53 receiving touchdowns, which are tied for the seventh-most in the league in that span.

The Seahawks visit the Kansas City Chiefs on Christmas Eve before finishing their regular season with games against the New York Jets and Los Angeles Rams.