EARTH CITY, Mo. -- The St. Louis Rams haven't been getting much in the way of good news on the injury front lately. But even now, as cornerback Trumaine Johnson appears to be tracking toward a return from a thigh injury, that progress nearly is canceled out by the lack of practice for cornerback Janoris Jenkins.

Jenkins sat out his second practice in a row Thursday as he continues to work his way back from a concussion. Jenkins remains in the concussion protocol and would need to make substantial progress in the next couple of days in order to be ready to play Sunday against Detroit.

On the bright side, Johnson was upgraded from limited to full participation in practice on Thursday and looks like he could be ready to return.

Tight end Lance Kendricks, who also is dealing with a concussion suffered last week, is ahead of Jenkins when it comes to going through the protocol. He was limited on Wednesday and upgraded to full on Thursday though he hasn't been fully cleared in the protocol yet.

The Rams potentially will have two roster spots to play with in order fill an opening in the secondary when they put end Robert Quinn (back) and safety T.J. McDonald (shoulder) on injured reserve.

Here's Thursday's full injury report:

Did not participate -- CB Janoris Jenkins (concussion), OL Andrew Donnal (knee), K Zach Hocker (right thigh), P Johnny Hekker (not injury related -- rest), DE Robert Quinn (back), S T.J. McDonald (shoulder).

Limited participation -- DE William Hayes (thigh), WR Wes Welker (calf).

Full participation -- TE Lance Kendricks (concussion), CB Trumaine Johnson (thigh), K Greg Zuerlein (right hip), QB Case Keenum (concussion).