Texas Rangers left-handed starter Matt Harrison, who will undergo an MRI on Thursday for a stiff back, has been removed from all baseball activities, according to general manager Jon Daniels.

Daniels said Harrison would return to Dallas on Monday to be examined by spine specialist Dr. Drew Dossett, who performed both of Harrison's back procedures last year.

"You hope for the best," Daniels told the Dallas Morning News. "But with everything he went through last year, there is a level of concern. Hopefully, it's just some irritation from getting going. ... He did a lot this winter without having any issues."

Harrison had back issues last April after just two starts and ended up having a herniated disc repaired at the end of the month. He was 0-2 with an 8.44 ERA in those outings.

The 28-year-old Harrison came into 2013 looking to build off an 18-win season in 2012. His performance earned him a five-year, $55 million deal, plus a club option for 2018.

"There's obviously some concern there from what happened last year," Harrison told The Associated Press. "I just hope that it's not a serious issue and something I can take a few days down and stay on top of my core program and get right back out there, and hopefully that's the case. But it's not fair to say that I'm not worried about it, because I've had a lot of issues recently."