When Minnesota United FC forward Nate Polak started feeling pain in his shoulder area after the first week of the pre-season, he figured that it was nothing to worry about.

"I thought I was just sleeping on it wrong, or something," he said.

But when it started to swell and bruise, and the veins started to pop out, he had to go to the trainers, and then to the team doctor. An ultrasound discovered that Polak had a blood clot in his shoulder - also known as thoracic outlet syndrome, a condition in which a nerve or blood vessel in the region of the clavicle is compressed, leading to clots.

For Polak, it meant a week in the hospital at the University of Minnesota, followed by a week in the Mayo Clinic, as two sets of doctors tried to break up the clot via various procedures. "That was rough," said Polak.

"I guess my first thought was 'When am I going to get back to playing again, and how’s this going to affect the rest of my season?'," he said. "I was just really worried about that. But it became a health issue - I kind of needed to worry about my health first. It was a scary moment. Nothing I’d ever expect to happen."

The 23-year-old, who joined Minnesota partway through last season after graduating from Hastings College, is currently on blood-thinning medication to try to lessen the clotting. He says he's feeling good, though, and the next step is to wait for surgery - a rib resection, where the rib in the area is removed in order to reduce the compression on the vein.

Coincidentally, Polak is the second local athlete to deal with this problem this spring. Twins minor-leaguer Deolis Guerra was hospitalized during spring training with the same issue, and had a rib removed in mid-March.

Once the surgery is done, Polak says his recovery time will be quick. "I'll be able to do fitness and touches on the ball," he said, "but the only thing in question right now is how long I'll be on blood thinners afterwards."

He won't be able to train with the team until the whole thing has run its course, however - it's just not workable while he's on blood thinners. Said Polak, "Taking a knock during training, or something like that, would be serious."

The team is not expecting him back at any point in the first half of the season, putting a hole in the team's forward depth. It's certainly tough on Polak, especially during a game like last Saturday's, in which the team was short up front. "I was really wishing I could have helped," he said.