Phillies' Harrison diagnosed with hyperthyroidism

Matt Harrison may have found the answer to his health issues.

The pitcher, who was recently sent to the Philadelphia Phillies in the Cole Hamels trade, has been diagnosed with hyperthyroidism, according to the Fort Worth Star-Telegram's Jeff Wilson.

Hyperthyroidism is notorious for causing weight loss, which is one of the symptoms Harrison's experiencing. The 29-year-old has been struggling to regain his velocity and is also having issues with back stiffness.

He was recently placed on the 15-day disabled list with lower back inflammation and has only pitched in nine games since the beginning of the 2013 season.

"I wouldn't bet on (him pitching this year)," Phillies interim manager Pete Mackanin told Nick Suss of MLB.com. "But like I told him yesterday, I said 'I know you feel bad, but we're looking at you for what we're about to become rather than this year. We're not really playing for a whole lot this year.'"

The left-hander is still owed $13.2 million over the next two seasons with a $13.25-million team option in 2018.