He will undergo an MRI on Thursday in Orlando and then be re-evaluated. After the game, he said he felt he'd avoided a serious knee injury.
"I've never hurt my knee before," Isaac said. "So as soon as it happened, I just naturally start thinking the worst. 'Wow man, it's over.' But as I was down there, it started to feel better and better just being down there. So I kind of felt, just the reassurance that I was going to be [OK]."
Isaac's legs got tangled as he drove to the basket at 9:57 of the first quarter and he crumpled to the floor, clutching his knee. He was taken off the court on a stretcher.
Isaac is in his third season with the Magic after being selected sixth overall in the 2017 NBA draft out of Florida State.
He went into Wednesday's game averaging 12.3 points and 7.1 rebounds.