The Sixers have rolled a gutter ball with their trade for Andrew Bynum

According to a report from ESPN's Brian Windhorst and Chris Broussard, Bynum injured his left knee while bowling this week.

Bynum is currently rehabbing his right knee and was not supposed to start basketball related activities until mid-December.

Speaking to the media prior to the Sixers victory against the Jazz Friday night, Bynum revealed he had suffered a setback in his other knee.

“I had a little bit of a setback, and we're just working through some issues with the right knee,” Bynum said. “I kind of have a mirror thing going on with my left knee. I don't know what's going on, but the doctors are saying pretty much that it's a weakened cartilage state.”