San Francisco 49ers safety Eric Reid will miss a few games with a posterior cruciate ligament (PCL) injury in his left knee. It's an injury that will force him to miss time but won't require surgery. On Monday, Jaquiski Tartt did not practice as the 49ers prepare for their Thursday night game against the Los Angeles Rams at Levi's Stadium. Tartt was listed on Monday's practice participation report with a neck injury and head coach Kyle Shanahan said he is questionable for the game.

"I know he's getting all his rehab," 49ers defensive coordinator Robert Saleh said of Tartt on Tuesday. "He's trying to get himself ready for Thursday."

On Sunday, Jimmie Ward was on the football field for the first time this season but his extended play was due to Reid's injury and the 49ers would like to remain cautious with him as he returns from a hamstring injury suffered at the start of training camp. He was limited during Monday's practice.

Saleh was asked how Ward looked over the course of Sunday's loss in Seattle.

"He held up well," Saleh responded. "Feedback was good. (He) feels good. Man, he looked fast, too. So, it's good to have him back. Hopefully, he can stay healthy."

If Tartt is unable to go on Thursday night, it leaves a pair of rookies competing for the opportunity to gain more playing time. They are seventh-round draft pick Adrian Colbert and undrafted rookie Lorenzo Jerome. Colbert is listed at 6-foot-2 while Jerome is listed at 5-foot-10. While one has a size advantage over the other, Saleh explained that height may not necessarily be a deciding factor when determining who might fill in.

"You have a prototype but I think football players come in all shapes and sizes," Saleh said. "They have all kinds of measurables. So, you'd love to have a certain measurable but, right now, the men we have in our room have to get it done."

Jerome has already played 12 defensive snaps this season, all of which came during Week 1 against the Carolina Panthers. Jerome was inactive against the Seahawks. While Colbert has been active, he has not yet played a defensive snap.

The 49ers' next practice will take place on Tuesday at 4:20 p.m. PT. There will be no media access available on Wednesday.