DENVER -- Todd Helton underwent an MRI on Monday, revealing disc problems that have caused ongoing pain in the Rockies' first baseman's lower back. The injury has kept Helton on the disabled list for more than a month.

"He's got a degenerative back," Rockies trainer Keith Dugger said. "It's the same problems he's been having, so we're going to take things slowly."

Helton began feeling healthy enough to hit off a tee and participate in soft toss last week, but his back pain flared up soon after. Helton has not participated in baseball-related activity since.

"It's frustrating," Helton said. "I thought it was pretty loose and I was ready to go out there. I did a little too much, took a swing, and I knew something was wrong. I'm back to square one now."

Helton had been struggling at the plate before going on the DL on July 3. In 81 games this season, Helton was hitting a career-worst .266, with seven home runs and 29 RBIs.

There is a real chance, with 48 games remaining, of Helton not playing again this year. But the five-time All-Star is trying to stay positive.

"I want to get back out there," he said. "Hopefully I'll start feeling better again."