Rockies' first baseman Todd Helton will undergo an MRI on his injured back on Tuesday to determine whether or not he will return to the team this season, according to The Denver Post. Helton has already missed 28 games because of the condition. He was making progress until last week when he felt pain while swinging a bat. "I took a bad swing, and I kind of hurt it," Helton said. "So here I am. I'm up and walking around, so that's good." Colorado is 8.0 games behind Arizona in the National League West, and 11.5 games behind Milwaukee for the Wild Card spot. "It's been frustrating," he added. "I thought I was getting close. I was looking at a rehab assignment when I got hurt, so from that regard it's frustrating."