That would mark only a nine-month absence since he sustained the injury in Week 15.
"Knee's feeling good - feeling real good, actually," Waddle told MLive.com. "I think I'm a little ahead of schedule. ... We haven't had any kind of setbacks."
Waddle started nine games in 2014 before being sidelined.
Waddle tore the ACL in a Week 15 game against the Vikings last season, and has been rehabbing the knee for about nine months. Recovering from an ACL tear usually takes around nine months.
"Knee's feeling good -- feeling real good, actually," Waddle said. "I think I'm a little ahead of schedule. It's been going really well, we haven't had any kind of setbacks. Each day I feel like I'm getting a little better. Hopefully I'll be back sooner than later."
Waddle's recovery might put him on the field for the Lions' Week 1 game this season.
"I think there's a chance," he said. "It just kind of depends on how the rest of the rehab goes. Just going in, working hard every day and trying to get better."
Waddle has felt ready to begin running for some time, but he is sticking with the prescribed schedule.
"It’s hard to hold back," Waddle said, per NFL.com. "I’m not going to lie. I’m doing everything I’m supposed to do. There’s no point in pushing it and doing something stupid and make everything you did worth nothing. I’m pushing it as much as I can push it."
Reiff has started 32 games at left tackle over the last two seasons. The Lions aren't sure that last year's right tackle
Reiff told the Daily Republic he doesn't care where he plays.
"I like playing, and wherever they want to put me, that's fine. I'll play," he said.