"Sore. It's better than it was last week," Portis said. "I'm playing this week, if that's what you all want to know. No ifs, ands, buts about it, I'll be playing."
Portis rushed for 68 yards on 15 carries in the 14-10 loss to Dallas despite not practicing at all last week.
"Friday, I didn't think it was possible for me to play," Portis said. "Saturday it was like, 'Maybe I'll be OK.' Sunday, it was like 'I'm playing.'"
Portis, the league's second-leading rusher with 1,063 yards, said he wasn't at full strength.
"I didn't have leg drive, and I couldn't high-knee and pull up out of stuff," Portis said. "But I think as far as running the ball, I did OK. But when you talk about breaking tackles and the burst of speed, I didn't have it, so that's what I'm working on this week."
Receiver Antwaan Randle El (ankle), guard Pete Kendall (knee), left tackle Chris Samuels (knee) and linebacker Marcus Washington (ankle) did not practice. All but Washington are expected to play Sunday.
Cornerback Shawn Springs, who has missed four straight games with a calf injury, returned to practice.