OAKLAND, Calif. --- Astros starter Collin McHugh prematurely exited Friday night's 9-8 loss to the Athletics because of a torn middle fingernail on his pitching hand, jeopardizing his availability for his next turn in the team's rotation.

The Astros described McHugh's injury as a "right middle fingernail avulsion." The righthander came out of the game after throwing his warmup pitches before the bottom of the fourth inning. He allowed three runs on four hits, including two home runs, in his three innings.

McHugh said the issue is the same one he had in 2015. It didn't cost him any starts then. He described it Friday as his fingernail digging into the nail bed beneath it, causing "cutting and bleeding." It occurred as he warmed up before the game. Once in the game it affected his ability to throw his cutter and his slider, he said.

Astros manager A.J. Hinch said he didn't think the team would know the severity of the injury until Saturday. McHugh, who's vying for the fourth spot in the Astros' postseason rotation, is next in line to start Thursday at Anaheim. The Astros currently have six starters in their rotation but had planned to cut down to five by Tuesday. It was expected they would do so by moving Brad Peacock back to the bullpen.

McHugh wore a band-aid on the affected finger as he spoke with reporters postgame. He said he had already started getting treatment for the issue. He attempted to endure it in Friday's start – the Astros tried super-gluing the nail between innings - but ultimately couldn't.

"I hate it for tonight. I was feeling pretty good coming into today," McHugh said after the game. "With the doubleheader tomorrow, you would've liked to save the bullpen as much as possible. But it didn't happen tonight. We'll work this week and try and get back and healthy for the next start."

Michael Feliz replaced McHugh to pitch the fourth inning. In all, the Astros used six different relievers to finish the game, in which they blew a 7-3 lead.