Joe Nathan put everything he had into rehabilitation following Tommy John elbow ligament replacement surgery in March of 2010 to be ready for the start of the 2011 season. And he accomplished that.

Yet he hasn't been the pitcher he wants to be -- or the Twins need -- posting a 7.63 ERA with opponents batting .353 off him.

Now with his elbow hurting, Nathan is headed to the 15-day disabled list to work the inflammation out of the area and hopefully return a better pitcher.

"You never want to have a setback to put you on the DL," he said. "This is a situation where we want to take care of this thing and kind of gradually get better as the season goes on."

"And doing what I'm doing now, it's just kind of keeping on a level. It is not getting much better. We feel like we have a pretty good plan as far as treatment right now."

Nathan doesn't know when he will return to the mound. He is eligible to come off the disabled list June 8, but it depends on when the soreness subsides and he's able to get on a throwing program and work on his pitches.

"I think I'm prepared for anything from 10 days to a month," he said. "I don't think I'm prepared for more than a month. I think if it starts to get longer than that it would surprise me."

A magnetic resonance imaging exam exam of his elbow Saturday confirmed the inflammation and nothing else. The Twins will send the MRI results to Mets doctor David Altchek, who performed the surgery last year.

Nathan hopes to be in position to finish the season strong, see improvement in his pitching and look forward to 2012, where can put his comeback behind him.

"It would be one thing if we would have been closer to the front of this pack and competing," he said. "... That, at least, makes the decision easier, to take care of this and make sure we do the right things for me."

James coming up

After their 1-0, 10-inning victory over the Angels on Saturday night, the Twins announced they will purchase the contract of lefthander Chuck James from Class AAA Rochester. James, who is supposed to be in uniform in time for Sunday's game, was 1-1 with a 1.57 ERA in 28 2/3 innings with the Red Wings.

Twins manager Ron Gardenhire said the former Atlanta Braves starter was pitching the best of anyone at Rochester, righthanded or lefthanded. He is the 12th player not on the Opening Day roster to be called up from the minors this season.

Capps OK

Everyone gets worried when a pitcher battles a sore forearm, because that can be a warning sign of ligament damage in the elbow.

"Me too," Twins righthander Matt Capps said.

Capps has had a sore forearm but pitched a 1-2-3 ninth inning Saturday and could have been used Friday. He said recent maintenance work on the forearm has made it feel a lot better.

Etc.

• According to the Elias Sports Bureau, the Twins' 6-5 loss on Friday was the second time in club history -- and first time since July 30, 1971 -- that they lost when leading by five or more runs going into the eighth inning. Since 1971, they were a major league-record 755-0 in those situations before Friday.

• Jim Thome was expected to have a cortisone shot in his right shoulder after Saturday's game and could play Sunday, although sometimes a day or two is needed for the shot to take affect. He was not in the lineup but did pinch hit against Angels starter Jered Weaver in the ninth inning, striking out.

• Lefthander Jose Mijares threw two innings in an extended spring training game in Fort Myers, Fla., and could be activated from the 15-day DL by Monday.