SANTA CLARA, Calif. -- Already without two of their most important players, the San Francisco 49ers added two more key names to the injury report Thursday when tight end George Kittle and cornerback Charvarius Ward did not participate in practice.

Kittle is dealing with a hamstring injury and Ward is battling hamstring and knee issues, according to the team. Neither player was on the field for the early open portion of practice, leaving their status up in the air for Sunday's game against the Los Angeles Rams.

Those absences come on the heels of the Niners placing running back Christian McCaffrey (calf, Achilles tendinitis) on injured reserve and losing Deebo Samuel to a calf injury against the Minnesota Vikings.

McCaffrey sat out that game and will miss at least the next three. Samuel is expected to miss "a couple of weeks," coach Kyle Shanahan said.

The extent of the injuries to Kittle and Ward is unclear at the moment, but both were listed as full participants in Wednesday's practice. Kittle was a first-team All-Pro in 2023; Ward was second-team All-Pro.

If Kittle can't play against the Rams, veteran Eric Saubert would likely step into the starting role. Jake Tonges is the only other tight end on the active roster, although Brayden Willis and Mason Pline are available from the practice squad for depth.

If Ward is unable to play, the Niners would likely turn to rookie Renardo Green, a second-round pick out of Florida State, to play more snaps in nickel packages with Isaac Yiadom starting outside opposite Deommodore Lenoir. Darrell Luter Jr. and Rock Ya-Sin are the other cornerback options on the roster.

Heading into this weekend, the Niners and Rams are both dealing with injuries to significant players. The Rams are missing top receivers Cooper Kupp (ankle) and Puka Nacua (knee) and offensive linemen Steve Avila (knee) and Jonah Jackson (shoulder), among others.