Vargas gave up a two-run homer to Mark Teixeira which sent the Royals to a 5-1 loss to the Yankees on Tuesday.
"I thought coming back off the DL, he was pretty down sharp," Yost said. "He made one pitch, tried to go down and away to Teixeira, and it came back middle-middle. But six punchouts, pretty darn good. Came back in good fashion."
"Didn't have any lingering effects from what was bothering me," he said. "Always got to look at that as a positive. Obviously, we wanted to win tonight. But we'll come out strong tomorrow."
Vargas hinted that he might have had enough strength to go past the fourth even though he had hit his pitch count.
"I felt good after the fourth," he said. "Skip felt it was a good move there to take me out and that's a good thing I think going forward, though."
The pitch count built up because of the six strikeouts.
"You'd like to get contact as quickly as possible, but you're never going to complain when you get swings and misses," Vargas said. "That tells you the ball is coming out of your hand the way you want to. Would I have liked a double play some of those innings? Sure. But all in all it was good."
Jeffrey Flanagan is a reporter for MLB.com. Follow him on Twitter at @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.