David Ortiz has undergone an MRI on both heels to rule out any complications as he recovers from an injury to his right Achilles tendon.

"That's where he's been feeling discomfort," John Farrell said. "It's been overall in both heels."

The Red Sox aren't sure if the discomfort has resulted from a different running style developed to compensate for the pain Ortiz has felt in his right Achilles.

"I don't think he's gotten to the point where he's subconsciously favoring anything," Farrell said.