Defensive end Sam Okuayinonu is back on the 49ers’ active roster after initially making the cut to 53 players at the end of training camp.
The 49ers on Saturday promoted Okuayinonu while placing defensive tackle Javon Hargrave and linebacker Curtis Robinson on injured reserve.
The 49ers also elevated two undrafted rookies from the practice squad: defensive tackle Evan Anderson and safety Jaylen Mahoney. Both players will revert back to the practice squad on Monday.
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Okuayinonu, Anderson and Mahoney are expected to be in uniform Sunday when the 49ers face the New England Patriots at Levi’s Stadium. Anderson and Mahoney are in line to make their NFL regular-season debuts.
Okuayinonu has appeared in two games this season. He has three tackles and a sack. He had a spot on the 49ers’ initial 53-man roster but was waived one day later in a series of moves.
Anderson (6-foot-3, 326 pounds) appeared in 39 games during his four-year career at Florida Atlantic. In his final college season, Anderson appeared in 12 games and had 57 tackles, 5.5 tackles for loss, 3.5 sacks and one forced fumble.
Anderson provides depth at defensive tackle with Hargrave out and presumptive starter Jordan Elliott listed as questionable with a foot injury.
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Mahoney (5-11, 200) appeared in 54 games with 45 starts in five seasons at Vanderbilt. In his final year, he started all 11 games and registered 59 tackles and a team-high six passes defensed. He was a team captain.
The 49ers this week released veteran Tracy Walker III from the practice squad in an apparent vote of confidence for Mahoney’s readiness to play.
Starting safety Talanoa Hufanga is listed as questionable for Sunday’s game due to an ankle injury. If Hufanga is unable to play, the 49ers would turn to Malik Mustapha or George Odum to replace him in the starting lineup.
The 49ers made the roster moves Saturday with Hargrave and Robinson expected to be out for the season.
Hargrave sustained a torn triceps in the 49ers’ Week 3 loss to the Los Angeles Rams. Coach Kyle Shanahan said there is an outside chance Hargrave could return if the 49ers make a deep run in the NFL playoffs.
Robinson suffered a torn ACL at the beginning of practice on Thursday. He is scheduled for season-ending surgery.