The prevailing thought was that the procedure was merely precautionary, that the tightness and soreness that forced Nathan out of Saturday's game against the Red Sox after retiring just one batter was simply a result of the breaking up of scar tissue following his October surgery to remove bone spurs and loose bodies in the elbow.
On Tuesday morning, however, the news Nathan delivered was not good. He was diagnosed with what was termed a "significant tear" to the ulnar collateral ligament in his right elbow. To repair it would require Tommy John surgery and he would miss the 2010 season, but Nathan will not immediately opt for that. Instead, he will rest and rehab, working to build up the elbow over the next week or two. After that time period, Nathan will make a determination if he can pitch with the injury or will need an operation to repair the tear.
"Right now, I want to take it one step at a time," said the 35-year-old Nathan, who appeared to have difficulty containing his emotions. "I'm going to work as hard as I can in that week or two to be as strong as I can and hope the arm responds, that it feels good enough to go out there and throw. I don't want to look past that right now. My thought is I'll be fine in a week or two and I'll be ready to go.
"Obviously, this wasn't the news I wanted to hear. It definitely came as a bit of a surprise. At the same time, I have to be patient right now. We'll see how it feels in a week or two."
Nathan believes the injury occurred when he was on the mound Saturday, an outing in which he struck out one and walked two before exiting. Whether he can build up his elbow enough to pitch effectively with the tear remains to be seen, but Nathan is committed to doing his best to make that happen.
"We're going to pursue some other avenues here," Twins general manager Bill Smith said. "We're going to let things quiet down for a week or two and see if we can get some of the soreness out. Trainers are going to work diligently on it to build up strength in that elbow, then we'll re-evaluate."
The results from Monday's tests are being sent to elbow specialist Dr. James Andrews, who performed the procedure in October. There isn't a strong history of pitchers being able to perform with a torn UCL. Reliever Takashi Saito had a 50 percent tear two years ago while with the Dodgers and didn't have surgery. Though he missed a chunk of the 2008 season, he saved 18 games that season and had a 2.43 ERA in 2009. Angels righty Ervin Santana was diagnosed with a mild tear last season, went the rehab route as well, and went 5-2 with a 3.18 ERA and two shutouts over his last 11 starts.
"Everybody's different, every case is different," Nathan said. "I could be one of those guys, I might not be. I'm going to do whatever I can now to give myself the best chance to go out there and get on the mound and help this team win. At the same time, I'm not going to let this go on too long. I know these guys have a decision to make. They have to prepare for a season, too. I will make a decision quicker, rather than later, and give them ample time to prepare."
Manager Ron Gardenhire said he and his staff will begin doing just that as Nathan attempts to rehab the elbow. It won't be easy to replace the guy who set a team record with 47 saves in 2009 and has collected the most saves in baseball (271) since '04. Around the clubhouse, there was concern for Nathan first and foremost, with worries about the team's fortunes put on the back burner for the time being.
"It's a terrible thing to go through as a pitcher because you're still uncertain what's going to happen," reliever Jon Rauch said. "You don't know if it's a situation that's going to require a little amount of rehab and be back or if it's going to require surgery. You're kind of stuck in limbo with what's going on, but we're behind him, we wish him the best and a speedy recovery."
"I think more than anything, it's not a baseball issue right now," starter Kevin Slowey added. "It's about Joe. He's a good friend more than he is a closer. He wasn't happy about the news, but he took it the way all of us would have. That's how it is right now, 'I've got to move forward from that.' I think we're all a little worried about him. Baseball is something he's done, and done very well, for a long time. It's tough to imagine him not being out there."
It wasn't just members of the staff who felt for their injured teammate. Outifelder Denard Span recognized what kind of loss it would be for the team should Nathan be out for an extended period, but also realized what this could mean for the closer if surgery is in his future.
"That's definitely bad news for the team," Span said. "He's a big component to our bullpen and pitching staff. I hope the best for him and his family. I hope he can get better and get back out there for us as soon as possible. It's more important for him to take care of his arm and make sure he can finish off his career the way he wants to."
The Twins could turn to some in-house options if Nathan is unable to return. Rauch has the most closing experience, with 26 career saves, 18 of which came in 2008. Matt Guerrier has developed as the team's top setup man, and it's possible the Twins could give him a crack at closing. Jesse Crain was once thought of as a future closer candidate, and before missing all of '09, Pat Neshek was thought of as a guy who could finish games if needed.
If the Twins want to look outside the organization, they could try to orchestrate a trade. The one who seems most readily available is the Indians' Kerry Wood, who is under contract for $10.5 million for 2010 with a vesting option in '11 if he finishes 55 games.
Nathan had been looking forward to helping the Twins win in 2010, and he was excited by the personnel moves made during the offseason and moving into the team's new ballpark, Target Field.
"That's probably the hardest part of this," Nathan said. "Yesterday, flying home, that's probably the one thing that was on my mind the most, was how excited I am for this club, the new stadium, a lot of factors. It's tough.
"I know if I can, I will. If I'm able to go out there and throw, then I'll give it a shot. The only reason I would get the surgery done is if I was unable to go out there. If it's like it was on Saturday, then there's just no chance."
Jonathan Mayo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.