Ryan Mattheus says his arm is fine

Nationals right-hander Ryan Mattheus left the Nationals’ win over the Reds last night in an unnerving scene, throwing three warmup pitches before the seventh inning and walking off the mound. The Nationals later called the injury right shoulder tightness, but Mattheus said even that characterization made it sound more serious than it was .

Mattheus was lifting weights after pitching Wednesday night, and was sitting in the dugout after getting a key strikeout to end the sixth inning Thursday. When outfielder Jayson Werth saw him stretching, he asked the pitcher why he needed to do that after having already been in the game. Mattheus said his shoulder felt a little tight, and Werth told pitching coach Steve McCatty, who promptly pulled Mattheus from the game.

“They did the right thing,” Mattheus said. “They didn’t have time to sit down and ask me, ‘Hey, how’d you feel?’ I didn’t have time to explain myself. I totally understand their decision, and when you’re in their shoes, you’ve got to get the guy out of there.”

Mattheus had just injured his elbow when he came to the Nationals in a July 2009 trade, and missed most of the 2010 season after Tommy John surgery. That injury, he said, happened because he pitched hurt, so he said he’s learned enough to back off when he’s hurt.

On Thursday, though, he said he probably could have stayed in the game.

“‘Tight’ can be misconstrued a little bit. It’s nothing serious,” Mattheus said. “Even the three warmup pitches I threw there in the seventh, I felt fine. I was kind of surprised when they came out. But they did the right thing.”

In the sixth inning, the Reds had runners on first and third with two out when Mattheus relieved Jordan Zimmermann. The Nationals had a 1-0 lead, and Mattheus knew he needed to go after shortstop Paul Janish early in the at-bat.

He got Janish to foul off a fastball, chase a slider two pitches later and, two pitches after that, Mattheus fired a sinker down and in, getting Janish to miss for a big strikeout.

“I came in and I threw strike one, which I think has been my problem in the last couple outings,” Mattheus said. “Being able to make a guy commit, I threw a good sinker down and in, and he swung.”