Gates missed the Chargers' previous two games -- the first time he has sat out in his eight-year NFL career -- because of a torn plantar fascia in his right foot. He said Wednesday that he wanted to practice in the days leading up to Sunday night's game at Indianapolis to gauge his progress.
Thursday was Gates' chance, as he participated in individual drills and a select number of team plays.
"I wanted to see how I would respond to defenders being in the way and making unexpected cuts in the flow of a route," Gates said. "Everything has been controlled to this point. I didn't finish, but I'm incredibly sore."
Gates clearly was in pain after practice, grimacing through an interview session. He said was able to move well, but he wasn't optimistic. He said he'll wait until Friday to determine if he truly took a positive step toward playing against the Colts.
"I did this kind of running last week and then I couldn't go for two days," Gates said. "I couldn't even walk on a treadmill. I don't know what my response is going to be, but I feel like I'm making progress. But it's so painful, and I have to figure out if I can play through that."
Gates also must factor in the artificial turf at Lucas Oil Stadium, which could be a deterrent. Gates hopes little steps like Thursday's practice will expedite his rehabilitation and get him back on the field, whether it's this week or in the future.
"The soreness is going to be there, and I have to deal with it," Gates said. "I'm trying to speed this process up as much as I can by working through the soreness, so I can get back on the field as quickly as possible."
Gates has 40 catches for 663 yards and nine touchdowns this season.
Gates' potential return comes just as Pro Bowl wide receiver Vincent Jackson is preparing to make his season debut after being activated off the roster exempt list Tuesday. Wide receiver Legedu Naanee, who missed the previous five games with a hamstring injury, took part in Wednesday's practice and was a limited participant Thursday.
The Associated Press contributed to this report.