Boston Celtics big man Daniel Theis knew something was wrong when he took a long step against the Detroit Pistons on Saturday and felt something pop in his right foot.

"Everybody knows their body and when something is wrong you know it," Theis said "The night was tough, but the next day the doc called me and said partial tear, it was really lucky, not long, so I was really relieved."

Theis, who has been struggling with leg injuries since last season, partially tore the plantar fascia in his foot -- an injury that could have been much worse. Theis tore his left meniscus in March and missed the rest of the season.

"This time it's going to be way shorter than the knee," Theis said. "The knee was a long process."

According to Theis, he will be in the boot for two weeks, after which he will be considered day-to-day as he begins running.

"All I know is that it didn't rupture," Brad Stevens said. "It's a tear in the muscle and supposedly it takes a few weeks before he can kind of retest it and make sure that it's in good shape and then move on from there."

Theis also suffered a left heel injury this year. Saturday's game was his best performance since returning to the floor, which made the latest injury particularly frustrating. But Theis said he is coping with positivity.

"I felt like myself again," Theis said. "I was able to run and jump, then this happens, but I'm going to be positive. I was positive over the seven months with my knee, and stay positive now, and keep working on my knee as well. When I come back running and shooting, I'll stay healthy and nothing can happen again."