Spencer was in shells as the rest of his teammates practiced in full pads during Wednesday's practice. Spencer was listed as limited.
His status for Sunday's game at Carolina is uncertain.
"We're trying to move forward with him and he has made progress," coach Jason Garrett said Thursday morning. "Just get to a point at some point, is he capable of going or not? So he did more yesterday and we're hopeful that as we go forward he can do more and play in this ball game. He's a big part of our defense."
Before his injury, Spencer was off to a strong start. He led the team with nine quarterback pressures and had two sacks, second to DeMarcus Ware's team-leading six. Spencer is also tied for the team lead with two tackles for loss.
The key for Spencer is being able to find some strength in that area to handle blockers and make tackles without re-injuring himself.
"It's not a question of responding," Garrett said. "It's about the level he needs to be at (to play) and you probably do a lot of different things to gauge that level whether it's working in the weight room or work with the rehab guys and again it's been promising. We've been optimistic at different points and you got to get to the point now, we can play in a NFL game. He just hadn't gotten there yet."
Victor Butler replaced Spencer in the Chicago game and picked up just one tackle and Alex Albright got the start in Baltimore and had three tackles and a tackle for loss.