NEW YORK - Glen Perkins wants to make sure there are no concerns about potential ligament damage in his elbow.
Yes, the Twins lefthander did have problems with his forearm last weekend and yes, forearm problems can lead to problems with the ulnar collateral ligament. But the ligament is fine.
"This was a radial nerve [issue]," Perkins said. "It was getting pinched or irritated, and we had found some inflammation around the nerve up on my upper arm."
The irritation led to weakness in his forearm. Perkins added that he had an X-ray and magnetic resonance imaging exam of the humerus area that detected the inflammation. After two days of rest and anti-inflammatory medication, he said he felt a lot better. He pitched a scoreless eighth inning Thursday night.
Perkins is a key member of the Twins bullpen, and the club wanted to be careful with him. They are still figuring out which pitchers can be relied on for late-inning situations.
"Getting Perkins back helps an awful lot," manager Ron Gardenhire said. "We know he can go out there for the eighth inning."
In 4 1/3 innings so far, Perkins has given up five earned runs. Even with the forearm problems, his fastball has averaged 94.8 miles per hour, according to the website Brooks Baseball. That's not far off his 2011 average of 95.6.
Gardenhire is trying to determine who can be an emergency catcher now that Luke Hughes has been designated for assignment.
"I'm still trying to decide our way through that thing," he said. "How we handle those situations."
Gardenhire said it won't make him reluctant to use Joe Mauer or Ryan Doumit as a designated hitter. "It's not a perfect scenario, though," Gardenhire said.
The Twins have 13 pitchers on the roster and will likely keep it that way until righthander Nick Blackburn proves he can start Tuesday against Boston. There's a chance the Twins could call up a catcher when they go back to 12 pitchers. Drew Butera is doing the best of the catchers at Class AAA Rochester, batting .250. Butera has even started a game in left field.
Twins closer Matt Capps threw four split-fingered fastballs in Wednesday's game, clocked from 86-89 miles per hour on the Yankee Stadium radar gun. One of them struck out Curtis Granderson.
It's a pitch Capps is using this year as an extra weapon following a rough 2011 season. Capps credited former Twins closer Eddie Guardado, who was in spring camp for a while as a special instructor, for helping him with the pitch. The pitch had good movement Wednesday, and Capps plans to use it more.
"The game is constantly evolving," Capps said. "They have made adjustments to me. I have to counteract that."
• Joe Mauer turned 29 years old Thursday.
• Blackburn will throw a light bullpen session Friday in St. Petersburg, Fla., and follow up with a full bullpen session Sunday. If both go well, he will start against the Red Sox on Monday.
• Derek Jeter's second-inning single gave him 3,110 hits, tying the Yankees shortstop with Dave Winfield for 18th on the career list.