Liverpool boss Jurgen Klopp admits Loris Karius' hand injury is "not cool".
Karius is facing surgery and will be sidelined for up to 10 weeks.
Klopp insists he hadn't yet decided who would be No 1 come the trip to Arsenal on August 14 but Mignolet is now certain to start ahead of veteran Alex Manninger.
Asked about the blow of losing Karius, Klopp told the Liverpool Echo: “You never want an injured player and there's never a good time with the timing of injuries.
“It's not cool for him, not cool for us but it won't change and we have to take it.
“We have another three goalkeepers. Everyone knows about the quality of Simon Mignolet. He's made a really good impression in the first few days back in training and we also have a very experienced one in Alex Manninger and a very young one in Shamal George.
“A broken bone in the hand for a goalkeeper isn't great. It's not the worst but it could have been even worse. Six, eight, 10 weeks out, whatever, is not the longest period but it's not too good either."