At this point you have to chalk it up to bad luck.
Just two days after Kris Dunn was diagnosed with a moderate sprain in his left MCL, Bulls forward Bobby Portis has suffered the same injury in his right knee. Like Dunn, Portis is also expected to miss the next 4 to 6 weeks.
Portis was running back in transition late Wednesday night in the Bulls' win over the Hornets when he planted on his right knee and went tumbling into the stands. He laid on the ground for an extended amount of time, and though he walked off under his own power was ruled out for the remainder of the game.