Stephan Bonnar believes he could return to action by the end of 2008, should his rehabilitation from reconstructive knee surgery stays on track.

Bonnar (11-4, 5-3 UFC), the light heavyweight runner-up on season one of "The Ultimate Fighter," last competed in October, when he stopped former training partner Eric Schafer on strikes at UFC 77. He was scheduled to fight Matt Hamill in April but injured his knee in training. The 31-year-old Indianan underwent surgery to repair the damage in March.

"It's going about as good as it can," Bonnar said. "I'm about halfway there. Whenever you get a ligament replacement, it's one of the longest injuries to recover from. I have a good surgeon, so I'm pretty optimistic."

Based out of Xtreme Couture Mixed Martial Arts in Las Vegas, Bonnar has been finished only once - by unbeaten Lyoto Machida - in 15 career fights. His epic war with Forrest Griffin on "The Ultimate Fighter" Live Finale in April 2005 has been credited with the sport's popularity explosion. Bonnar - who owns victories against Keith Jardine and James Irvin - hopes to be able to resume training by September and aims to return to competition towards the end of the year. Time away has given him pause to reflect on his career.

"When something like this happens, a serious injury, it makes you not take things for granted," Bonnar said. "I'm thankful I'm able to do it."