Nathan, 35, complained of tightness in his surgically repaired right elbow during an exhibition game against the Boston Red Sox Saturday in Fort Myers, Fla. He was removed for precautionary reasons, and on Sunday Nathan told reporters he was heading home to Minneapolis for an MRI exam, MLB.com reported.
Nathan said team doctors believe the soreness is likely the breakup of scar tissue from the top reliever's Oct. 20 surgery to remove bone spurs and loose bodies, not a new injury.
But, he said, an MRI exam will be performed to confirm that tentative diagnosis.
"Everything is looking good, as it not being super serious," Nathan told MLB.com. "As far as tears or anything, it doesn't look like it's anything like that. That's a positive, and I'm going up there with positive thoughts."