Nathan added that he's planning to throw a bullpen session for Monday.
"It was quick, because I wasn't planning on doing it," Nathan said of Saturday's pitches. "When I came in from long-tossing today, it felt so good. [Pitching coach Jeff Jones] said let's get on the bump and get some touch-and-feel from throwing on the slope and getting that angle. Good to do that. Monday, I probably want to get a full session in, so it was nice to get on it today."
At 40 years old, Nathan admitted he was worried the strain might not heal properly, but Saturday was a step in the right direction. Nathan has faced just one batter this season, striking out Minnesota's Torii Hunter to earn a save on Opening Day.
"Felt good, which is nice; a much better day," Nathan said. "A few days ago, I was a little bit like, 'This thing may never [get right].' That's the way strains are. One day, it may never get better, and then one day, it does."
Chris Vannini is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.