UFC lightweight champion Anthony Pettis is having a hard time staying healthy.

According to a report from Ariel Helwani on Wednesday's UFC Tonight on Fox Sports 2, Pettis has completely torn the posterior cruciate ligament or PCL in his left knee. Coincidentally, this is the very same knee he injured in his last fight in August where he won the title from then-champion Ben Henderson.

After suffering that injury in his title-capturing performance, Pettis' partial tear in his left PCL required he rest six to 8 weeks. Pettis allegedly did exactly as his doctor and medical professional suggested, but in his first day back to full training, checked a kicked that fully tore the very same ligament.

Pettis has consulted with three different doctors to evaluate the injury and his options, all of whom have suggested different remedies. He's also headed to Los Angeles, Calif., next week see a fourth. If the final doctor suggests he have surgery to correct the problem, Pettis told Helwani he will elect to take that option. If he is able to avoid such a drastic treatment, the rehabilitation process is only eight more weeks, but the champion reportedly believes he is ultimately likely to have surgery.

The champion was originally expected to make his first title defense against T.J.Grant in December on the UFC on Fox 9 fight card, but the opponent was changed to Josh Thomson when Grant withdrew to ongoing concussion symptoms in September. Soon thereafter, however, that bout was entirely withdrawn from the card and the flyweight title rematch between champion Demetrious Johnson and Joseph Benavidez took its place as that event's headliner.

Since moving to the UFC, Pettis spent time away from competition in 2012. He had shoulder surgery in April and suffered a staph infection in July. A June 2013 injury also sidelined the Milwaukee, Wisconsin-based fighter from a meeting with Jose Aldo.