"We couldn't get it to really stop," McHugh said, adding that it started as he was warming up before the game. "We put some superglue on it, tried a couple different things down in the dugout. Couldn't really get the result we wanted."
McHugh said that the cutter and slider were most affected by it, but he was able to pitch through it for three innings. But as he warmed up for the fourth, he repeatedly looked down at his throwing hand, which set off red flags for Astros manager A.J. Hinch.
"It was a dilemma about whether to send him back out and try to get a couple outs out of him," Hinch said. "We had the lead, he was throwing the ball fine and we eliminated one of his pitches. When he went out and warmed up, after every pitch, he started looking at his nail, so that's when I decided to pull the plug."
McHugh allowed three runs on four hits (two homers) in three innings of work. He walked one and struck out one while throwing 50 pitches.
The Astros brought in right-hander Michael Feliz for McHugh in the fourth. Feliz was activated before Friday's game after missing more than a month with right shoulder discomfort. The Astros ended up using six relievers on the night, something that frustrated McHugh.
"I hate it. I hate it for tonight," McHugh said. "With the doubleheader tomorrow, you'd like to save the bullpen as much as possible. Didn't happen tonight. We'll work this week and try to get it back healthy for the next start."
McHugh said he had the same issue happen a few years ago and was able to make his next start. Hinch added that the team would evaluate McHugh again Saturday.
Alex Simon is a reporter for MLB.com based in the Bay Area. Follow him on Twitter at @alexsimon99. This story was not subject to the approval of Major League Baseball or its clubs.