SANTA CLARA, Calif. — The San Francisco 49ers have placed All-Pro running back Christian McCaffrey on the injured list due to persistent injuries to his calf and Achilles tendon.

Saturday’s move means McCaffrey will miss at least four more games after missing the season opener. He is eligible to return for a Thursday night game at Seattle on Oct. 10.

McCaffrey was injured early in training camp and missed four weeks of practice before returning to the field on a limited basis last week. He was a late starter against the Jets on Monday night and is now sidelined again after being sore following Thursday’s practice.

McCaffrey led the NFL with 2,023 yards from scrimmage last season and tied for the league lead with 21 touchdowns. He won the AP Offensive Player of the Year award.

The Niners made up for McCaffrey’s absence with a strong performance from backup Jordan Mason, who had 28 carries for 147 yards and a touchdown in San Francisco’s 32-19 win over the New York Jets. Mason is scheduled to start again on Sunday at Minnesota.

After missing 23 games in his last two full seasons with Carolina due to injuries, McCaffrey has been fit the past two seasons.

He missed just one game total in 2022-23 — a meaningless contest in Week 18 last season for San Francisco while nursing a sore calf. His 798 combined touches from scrimmage in the regular season and the playoffs were the third-most for a player in a two-year period in the past 10 years.

Now San Francisco will likely lean heavily on Mason, a former undrafted free agent out of Georgia Tech who had 83 carries in his first two seasons. He had at least 10 touches only twice before the season opener, when his 28 carries were the most by a 49ers player in a regular-season game since Frank Gore had 31 against Seattle on Oct. 30, 2011.

The Niners also have fourth-round rookie Isaac Guerendo and Patrick Taylor Jr. on the active roster. Guerendo played three touchless offensive snaps in the opener. Taylor had 65 carries for Green Bay from 2021-23.

San Francisco also has signed safety Tracy Walker III from the practice squad for Sunday’s game against Minnesota.