The Reds are at the start of a bizarre week for the club, with two games in less than 24 hours across two competitions and two continents.
It has seen Critchley given duties as manager against Aston Villa, and with the entire senior squad—barring those injured—heading out to Qatar for the Club World Cup, he will call upon a youthful squad at Villa Park.
Elliott and Brewster—who is suffering with a knock—were cut from the travelling squad on Sunday morning, but there is still the possibility that they and others could fly later.
Critchley revealed as much in his pre-match press conference on Monday morning, though he gave no indication on who is on Jurgen Klopp‘s standby list.
“I believe there’s a flight waiting. It might depend on how they play in the game, so we shall see,” he told reporters.
“I think one or two might take that journey—I might try and sneak on the plane myself!
“So I’m sure one or two will go. [But] I honestly don’t know [who] in this moment in time.
“Anything can happen tomorrow night. We shall see what happens during the game and see who gets the call after.”
It would make sense for at least one of Van den Berg and Hoever to join the first-team squad, while Elliott and Brewster are shoo-ins if fit.
But it is unclear whether they would be eligible to play in the Club World Cup, and if they travel it could simply be to take part in training, particularly as Joel Matip, Dejan Lovren and Fabinho are all out injured.
Neco Williams and Curtis Jones have already travelled, and should therefore be involved against Monterrey on Wednesday evening.