Clelin Ferrell has a Knee Injury

Clelin Ferrell left the 49ers' 21-20 loss to the Rams with a knee injury and did not return. 

Afterward, head coach Kyle Shanahan said the injury doesn't involve the ACL or the MCL, which is good news. In the locker room, Ferrell told reporters that leaving the game was a precaution, and that he expects to play in the 49ers' first postseason game two weeks from now.

Shanahan will provide the media with the exact injury diagnosis on Tuesday when he speaks to the media on his weekly conference call.

Ferrell is one of the unsung heroes on the 49ers defense -- they absolutely will need him in the playoffs, because he's one of their best run defenders. He's not much of a pass rusher, but he sets the edge beautifully against the run, which means he doesn't let running backs or quarterbacks get past him and run to the perimeter. He forces them back between the tackles.

Of all the 49ers defensive ends, Ferrell is their best edge-setter -- much better than Nick Bosa, Chase Young and Randy Gregory. Those three are pass-rush specialists. Setting the edge is secondary for them. Lots of times they'll give up containment on run plays because they were rushing the quarterback expecting a pass.

One of the 49ers' only weaknesses is their run defense -- statistically, it's subpar, and that's with Ferrell on the field. Without him, a subpar run defense gets much worse.

The 49ers need Ferrell for the playoffs, and it seems like they'll have him. They may have dodged a bullet.