Atlanta Braves starting pitcher Mike Hampton underwent an MRI Thursday for his ailing back and the results showed he has a herniated disc that could sideline him for the rest of the season. Hampton, who was placed on the 15-day disabled list earlier in the week, received an epidural injection for his back, but was advised not to do anything except rest for the next several days. The veteran lefthander will likely be re-evaluated sometime next week and is eligible to return from the DL on September 4, although that seems doubtful. Hampton, who was scheduled to pitch Wednesday's finale against the Chicago Cubs, is on the disabled list for the fourth time this year. He has also been bothered by stiffness in his left forearm and has pitched a total of just 10 1/3 innings since the start of June. The 32-year-old first hurt his back while getting out of a whirlpool at San Francisco's SBC Park on July 19 and aggravated the injury in an August 19 start versus San Diego. In that last start against the Padres, Hampton was roughed up for seven runs and 11 hits in just 3 1/3 innings. Hampton is 5-3 on the season, while pitching to a 3.50 ERA.