WASHINGTON -- Right-handed reliever Ryan Pressly left the first game of Sunday's doubleheader against the Nationals with right triceps soreness and is day to day.

Pressly relieved left-hander Scott Diamond in the fifth inning and gave up a two-run double to Anthony Rendon. He was able to get out of the inning by getting pitcher Jordan Zimmermann to ground out to end the inning.

Pressly came back out for the sixth but left the game while facing Ryan Zimmerman after giving up a one-out single to Steve Lombardozzi. He was visited at the mound by Twins manager Ron Gardenhire and assistant athletic trainer Tony Leo and ultimately came out of the game.

Pressly, though, said he's hopeful it's just a minor injury. He will know more on Monday, but checked out just fine after being looked at after the game.

"[It] felt like a stinger right in the back of my triceps," Pressly said. "It was really weird. I've never had anything like that happen to me before. But I came in and did the tests and everything came back fine. So I'll probably come in tomorrow and throw a little bit to see if there's any discomfort. But as of now, I don't feel anything. It was just more scary than anything."

Pressly, a Rule 5 pick from the Red Sox, has been a pleasant surprise for Minnesota this year with a 1.24 ERA in 20 appearances.