San Francisco 49ers running back Christian McCaffrey will miss Monday’s game against the New York Jets due to a calf injury.

The 49ers announced McCaffrey’s status on the team’s inactive player report shortly before kickoff. Former All-Pro safety Talanoa Hufanga is also among San Francisco’s inactive players after suffering a knee injury that sidelined him at the end of last season. Jordan Mason will start at running back.

McCaffrey was initially listed as questionable for Monday’s game on San Francisco’s injury report released Saturday. Hufanaga’s participation was previously considered questionable.

The news that McCaffrey is out comes as a surprise after McCaffrey and head coach Kyle Shanahan repeatedly assured fans and media throughout the preseason that he was on track to be ready to play in Week 1. McCaffrey first sustained the calf injury in August at the start of training camp.

McCaffrey said on Aug. 9 that his absence from practice was considered a “warning” and that he would be ready if the 49ers had a game that day.

Shanahan has said throughout the preseason that he expects McCaffrey to play in Week 1. McCaffrey participated in practice for the first time last Tuesday, so he is on track to play Monday night.

He was then listed as a limited participant in Thursday’s practice with an Achilles/calf injury before receiving a questionable designation on Saturday. Shanahan told reporters Thursday that the Achilles injury was nothing new and was related to his calf injury in training camp.

McCaffrey was seen performing light exercises during practice on Thursday.

It was not immediately clear on Monday whether McCaffrey had suffered a setback or whether the 49ers had excluded him from the game as a precautionary measure.

McCaffrey is a three-time All-Pro. He led the league in 2023 with 1,459 rushing yards and 2,023 yards from scrimmage. He is tied with Dolphins running back Raheem Mostert for the NFL’s all-time leading touchdown leader (21). He was named NFL Offensive Player of the Year.

The 49ers enter the season having already reached the Super Bowl and are among the favorites to return to the Super Bowl from the NFC. McCaffrey, when healthy, has been a key part of San Francisco’s success and is expected to return in 2024.