Nathan faced three batters and threw 20 pitches. He walked two batters and was removed following a walk to J.D. Drew.
He was upbeat after the shortened outing and said doctors had warned him that the type of surgery he had would bring days like this in his recovery. He said he will be re-evaluated Sunday and, as of now, does not expect his spring training regimen to change.
"They said it may be scary, but you've got to understand that you're going to go through moments like this," Nathan said.
Though he was relaxed and seemed to take it in stride, he confirmed that the doctors were right, and that it is scary.
"Definitely," he said. "It's never fun when you get pulled out of a game, especially by the training staff. It's just a little speed bump here. We'll see where it goes."
Nathan said he felt "awesome" in the bullpen warming up. But, as he noted, while everything has gone smoothly in his rehab and recovery, he hasn't reached the intensity level in bullpens and live batting practice -- especially with his hard, biting slider -- that he did in Saturday's game.
Nathan, 35, had surgery to remove two bone spurs and some bone chips from his elbow in October. He revealed shortly after a season in which he had 47 saves that his elbow was not right for much of it.