49ers RB Christian McCaffrey (calf) sidelined in win over Jets.

SANTA CLARA, Calif. -- Despite expressing confidence on Friday that he would play, San Francisco 49ers running back Christian McCaffrey missed Monday night's season opener, a 32-19 victory over the New York Jets. McCaffrey has been managing calf and Achilles injuries since early in training camp, as revealed by coach Kyle Shanahan on August 6. At that time, Shanahan indicated McCaffrey would be sidelined for a couple of weeks and would not participate in the preseason. However, the hope was that McCaffrey would recover in time for Monday's game. On Friday,

McCaffrey even expressed optimism about handling his usual heavy workload, and general manager John Lynch told KNBR radio that morning that McCaffrey would "be out there and ready to roll." Despite participating in four limited practices throughout the week, McCaffrey was ruled out about 90 minutes before the game and was listed as one of the team's six inactives (plus the emergency third quarterback). Although McCaffrey was listed as questionable, his teammates and coaches remained hopeful he could play and perform at his usual level.

"He looks like Christian to me," said run game coordinator Chris Foerster on Friday. "You need to practice, so for those who haven't practiced, I don't want to say there's rust, but there's always a little adjustment because they haven't been doing it every day. There's just that daily grind. But he's looked good."

McCaffrey faced a similar injury at the end of last season. He sustained it during a Week 17 victory over the Washington Commanders and did not play in the subsequent meaningless Week 18 matchup against the Los Angeles Rams. He made his return in the NFC divisional round against the Green Bay Packers about three weeks later. Shanahan mentioned on Saturday that McCaffrey's current injury resembles that previous one. Before resuming practice on Tuesday, McCaffrey appeared to move well and reported feeling "much better" when he spoke with reporters on Friday. 

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As the NFL's reigning Offensive Player of the Year, McCaffrey had an impressive 2023 season, amassing 1,459 rushing yards, 564 receiving yards, and 21 total touchdowns. In his absence, Jordan Mason made his first career start, impressively rushing for 147 yards on 28 carries and scoring a touchdown. Veteran Patrick Taylor Jr. and rookie Isaac Guerendo were the other active running backs on Monday night, though neither saw any carries. Elijah Mitchell, last season’s backup running back, is on injured reserve and out for the year due to a hamstring injury.