http://www.bloodyelbow.com/2013/11/1...n-ufc-on-fox-9

UFC lightweight champion Anthony Pettis is one of the most exciting fighters in MMA today, but his biggest problem in the UFC has been his ability to stay healthy. Dana White told the media at last night's UFC Fight Night 32 press conference that Pettis currently has an unspecified knee injury, but will still defend his title vs. Josh Thomson on December 14th at UFC on Fox 9. Fox Sports has more details:

White did not specify Pettis’ injury, but said Pettis has spent the last two days in Las Vegas, seeing Dr. Steven Sanders, an orthopedist at Bone & Joint Specialists. After examining Pettis, Sanders informed him that no surgery would be necessary to address his problem.