Philadelphia 76ers prized big man Joel Embiid has missed 12 of the team’s last 13 games. After it was revealed Saturday that the rookie suffered a small meniscus tear in his left knee, reports out of the Sixers camp indicate that it’s the bone bruise in the same knee that has become more of a concern.

As initially reported by Derek Bodner of USA Today, the possibility of the injury being a pre-existing condition is being explored. Joel Embiid suffered an awkward fall on Jan. 20 against the Portland Trail Blazers. The injury was initially diagnosed as a knee contusion before an MRI revealed the low-grade tear. Embiid returned to action a week later against the Houston Rockets, putting up 32 points, seven rebounds, four assists, three steals and two blocks. He then experienced swelling in the troublesome knee two days after the game. He has not played since.

As noted by Bodner, Joel Embiid told CSN Philly Saturday that he wasn’t healthy. “It’s been on and off. Work out and then [the knee] wells up a little bit, and then I got to slow it down. It’s all about patience,” the rookie sensation said.

Joel Embiid, who continued to be out of action – missing Monday’s game against the Charlotte Hornets, is expected to be out at least until the All-Star break, according to CBS Sports. After starting the season with a logjam at center, the Philadelphia 76ers now have a void at the five spot, having recently decided to keep Jahlil Okafor out of the lineup amid trade rumors. Nerlens Noel has taken over Embiid’s starting spot, with Richaun Holmes backing him up.

Joel Embiid’s injury is not expected to require surgery. While a timetable has not been set for his return, the Cameroonian is being listed as day-to-day.