Phillips went on medical leave Dec. 14. Linebackers coach Reggie Herring ran the defense in his absence, and the Texans lost their next two games.
The 64-year-old Phillips surprised his players when he showed up at a meeting Monday. The Texans (10-5) were back at practice on Wednesday to prepare for the regular-season finale against Tennessee (8-7).
"It's good to be back," Phillips said. "It's not as funny now as it was before I was going in. I'm a little more sore than I thought I'd be. It's taken a lot out of me, but I'm working my way back, doing what the doctors say."
Phillips mingled with his players during the practice, but walked to the sideline late in the workout to sit on a golf cart with his father, Bum, the former coach of the Houston Oilers.
Coach Gary Kubiak is hoping Phillips will feel strong enough to work from the press box Sunday.
"It's good to have him back," Kubiak said. "I know it's good with the players. Got to be smart with him out here, make sure we don't get him banged around. But it's good to have him back out here and see that he's feeling much better."
Phillips was hospitalized for eight days, and says he's only now getting back to eating regular food.
"I'm starting to feel better and better," Phillips said. "I'll feel good, and then all of a sudden, my energy level does go down a little bit. But that'll get better as it goes."
Houston's defense has made a dramatic turnaround from 2010 in Phillips' first season, ranking second overall (281 yards per game). The Texans have already set a single-season record for sacks (41) and rank 10th in takeaways (26).
Phillips said the hardest part of his recovery is over, and returning to his regular schedule this week has lifted his spirits.
"Once you get into your routine, once you get to start eating and start being with the players and with the team, in the meetings and so forth, then everything gets easier," he said. "I'm just starting out, solid foods now. Once I get back to normal, which seems to be the case right now, that will get better and better."
Kubiak visited Phillips in the hospital and was relieved to see him back on the field again.
"Just for me, knowing what he went through, to see where he was then and where he's at right now, it's a great feeling," Kubiak said . "It's one thing you can't take for granted in life, your health. It's good to see him back out here, and I know we all appreciate it. The players are glad to see him back."