SANTA CLARA -- As the 49ers begin preparations to face the Los Angeles Rams in the regular-season opener Monday night, their depth in the secondary is already being tested.
Chris Davis, who has been the team's top nickel back since the opening of training camp, did not practice Tuesday due to a hamstring injury. Cornerback Keith Reaser was also sidelined with an ankle injury. If Davis and Reaser are unable to play, right cornerback Jimmie Ward would likely move to nickel back on passing downs with either Dontae Johnson or rookie Rashard Robinson taking over on the outside.
Meanwhile, running back Carlos Hyde was fully cleared to practice on Thursday. He was not listed among the six players who were limited or did not practice. Hyde is returning from sustaining a concussion in the Aug. 26 exhibition game against the Green Bay Packers.
Davis, Reaser and defensive linemen Glenn Dorsey were the only 49ers who did not practice.
Earlier on Thursday, 49ers coach Chip Kelly said he expects Dorsey to be available to play Monday, barring a setback. However, Dorsey's absence from the team's practice session places his status for Monday's game in serious doubt. Dorsey did not take part in team drills during training camp and did not see action in any of the team's four exhibition games. He sustained a torn ACL in his right knee in November.
Defensive linemen Arik Armstead (shoulder) and Quinton Dial (knee), along with linebacker Nick Bellore (knee) were limited during Thursday's practice.