Stewart still unsure of return date for final NASCAR season

Tony Stewart still doesn't know when he'll be back in his car to begin his final NASCAR season.

And yes, the three-time Sprint Cup series champion says he's still done after this year.

Stewart defied his doctors' wishes with a cross-country flight to Nevada this week because he couldn't sit at home any longer.

Rest is necessary for healing from a back injury, but Stewart felt compelled to support his teammates and employees at Las Vegas Motor Speedway this weekend when NASCAR opens its three-race Southwest swing.

Stewart will have X-rays next week in North Carolina on his back, which was injured in a low-speed dirt buggy accident. He had surgery to stabilize his broken vertebra, but his doctors haven't examined his progress or allowed him to begin rehabilitation.