The 19-year-old is now fit after recovering from injuries that have kept him on the sidelines since January 2018.
The striker was an unused substitute in a Premier League match against Crystal Palace back in April 2017, and now looks set to appear on the teamsheet at Anfield on Tuesday night.
When asked if Brewster would be part of the 18-man squad for the Barcelona game, Klopp said: "Yes, there is a big chance. It’s nearly sure. It’s guaranteed.”
The Reds boss added: “He’s ready.