San Francisco 49ers star tight end George Kittle is unlikely to play Sunday against the Seattle Seahawks because of a hamstring injury, sources told ESPN.

The 49ers want to see how Kittle is feeling pregame before making any final decision, according to sources. But they were not optimistic Saturday night that the five-time Pro Bowler would be available against Seattle and already were making plans to be without Kittle.

Fortunately for San Francisco, it is not considered a long-term injury, and Kittle will have a realistic chance to return for next Sunday’s game in Green Bay against the Packers, according to sources. But it is going to be challenging to play Sunday against the Seahawks, and there was concern earlier in the week that this might be the case.

San Francisco is more hopeful and optimistic that Pro Bowl offensive tackle Trent Williams will be able to make it back from his ankle injury that prevented him from practicing Friday, according to sources. Williams believes he can play against the Seahawks, but the 49ers still will evaluate him pregame to make sure he feels well enough to play.

The Niners are not as encouraged about Kittle, who has been dealing with a strained hamstring that he suffered last Sunday against Tampa Bay, where he caught a decisive touchdown pass that helped San Francisco win the game. Kittle did not practice Wednesday before being limited Thursday and Friday.

Kittle is regarded as one of the NFL’s toughest players and rarely misses time due to injury. He was sidelined for Week 3 of this season, marking the first time he missed a game due to injury since 2022, when he was sidelined for the first two games of the season with a strained groin. Kittle also played through a sports hernia last season that required offseason surgery.

If Kittle cannot play, Eric Saubert would start in his place, but there will be an added need for Pro Bowl running back Christian McCaffrey to step up in his second game back in the lineup. McCaffrey missed the first eight games of the season with calf and Achilles injuries but returned last Sunday to carry the football 13 times for 39 yards and catch six passes for 68 yards.

The 49ers continue to have to overcome losses and adversity on a near weekly basis. Wide receiver Brandon Aiyuk suffered a season-ending knee injury in Week 7 versus the Chiefs, Williams is now hobbled and Kittle is unlikely to play.

Kittle’s injury marks the latest setback in what has been a challenging week for tight ends across the league. The Lions are playing Sunday without Sam LaPorta against the Jaguars, while the Bills are without Dalton Kincaid against the Chiefs.