Isak made his comeback on April 8 in the Champions League after being out for several months due to the broken leg he suffered in the days before Christmas Eve.
"We have tried to be very careful since he came back," says Slot.
He has since played in four Premier League games. He last came on against Chelsea but missed the previous match against Manchester United completely due to a groin strain.
Nilsson Lindelöf replaced
Isak was unavailable when Sweden secured a World Cup berth in North America at the end of March through playoff victories against Ukraine and Poland, but he was named in national team manager Graham Potter's World Cup squad earlier this week. Sweden will face Tunisia in the opening match on June 15 in Monterrey, Mexico.
However, national team defender Victor Nilsson Lindelöf started on Friday for Aston Villa in midfield but was substituted after the first half against Liverpool.
From the bench, the Swede watched teammate Ollie Watkins secure a Champions League spot for next season. Watkins first made it 2-1 in the 57th minute and just over a quarter of an hour later added a 3-1. John McGinn extended the lead to 4-1 in the final stages before Virgil van Dijk reduced the deficit in stoppage time with his second goal of the evening.
Liverpool are fifth.
With 62 points and one game left to play, Aston Villa have secured a top-five finish, guaranteeing a place in Europe's premier club competition.
Reigning Premier League champions Liverpool are fifth on 59 points, four and six points behind Bournemouth and Brighton respectively, both of whom have one game in hand.
