The Egypt forward was forced off at Anfield on Wednesday after scoring in Liverpool’s 4-0 victory against Galatasary, a result that took them through to the quarter-finals of this season’s Champions League.
In-form Salah, 33, has scored in three of his past four starts after a lean spell.
“It’s unusual,” Slot said at his pre-match press conference on Friday. “As a result of that I think you can expect the outcome. So, (he’s) not available for tomorrow.”
Slot gave no timeframe for Salah’s recovery.
“The good thing for Liverpool and for us is that we go to an international break,” he said.
“The bad thing for Egypt is that he can’t go there.
“We are hoping also with what Mo has shown in the past that he can recover faster than other players might in similar situations because he takes such good care of his body. History has shown that he can be earlier back than some others.
“But it’s only two weeks until we go again so let’s hope in that period of time he can be back.”
Reigning champions Liverpool are fifth in the Premier League table, two points behind fourth-placed Aston Villa, with the top five teams almost certain to qualify for next season’s Champions League.
They face Manchester City in the FA Cup quarter-finals on April 4.