LOS ANGELES -- A new development may help explain why Chicago Bulls point guard Derrick Rose is still hesitant to return to the court.

ESPN's Doris Burke spoke with the former MVP before Sunday's game against the Los Angeles Lakers and reported that although Rose has been taking full contact in practice for well over a month, his hamstrings are "on fire" after those workouts. Rose added that he won't return to the court until he's past those issues.

A team source told ESPNChicago.com on Friday that one reason why Rose has been hesitant to play despite being medically cleared is because he still is struggling to dunk the same way off his surgically repaired left knee.

For his part, Bulls coach Tom Thibodeau on Sunday repeated the same line he's used for several weeks now when asked about Rose's possible return this season.

"We'll cross that bridge when we get there," Thibodeau said before the game. "For us right now the guys that are playing have to concentrate on their improvement and our next opponent. Derrick has to concentrate on his rehab. And until that changes that's the way it has to be and that's the way we're approaching it."

Rose did not sit on the bench during the first half of Sunday's game. He again went through his usual pregame routine of jump shots and cardio Sunday.

Information from ESPN's Doris Burke was used in this report.