Petr Mrazek (17 saves) replaced Neuvirth 8:07 into the second period. Hakstol didn't have an update on Neuvirth, who was activated from injured reserve Wednesday after missing 18 games with a lower-body injury.
"I said before, when you go in, always important are the first couple stops," Mrazek said. "If you can make a save, you can get into the game. After that I felt pretty good."
The Avalanche have lost three of their past four games while scoring five goals. They went 0-for-3 on the power play Wednesday and are 1-for-13 in the past four games.
"Generally, we've counted on our power play to give us at least one [goal] a night, so there's one we're missing in the last couple games," Avalanche coach Jared Bednar said. "The power play wasn't great again tonight, deliberate, too slow with the puck, not moving enough with it, not letting the puck do the work. Just a little bit too slow for me. Not enough attack mentality right now."
Hammond made his Avalanche debut because goalies Semyon Varlamov (ill) and Jonathan Bernier (hand) were unavailable. He spent Wednesday morning in transit after being recalled from San Antonio of the American Hockey League.
"I think it took me a period to get my legs under me," said Hammond, whose previous NHL game came Feb. 7, 2017 with the Ottawa Senators. "The unfortunate part is, I guess the game-winning goal ended up getting scored in that period, but as the game went on I settled in and started to feel better. I felt pretty good in the second and third."
The Flyers took a 2-0 lead in the first period.
