Speaking to reporters, Slot would only commit to Alexander-Arnold playing against Manchester United on Sunday.
He said: "I can tell you that he's playing on Sunday and hopefully he'll bring the same performances as he's brought in the last half year. I think everybody saw how great a first half of the season he had, how much he is here, how much he wants to win here.
"I see him on the training ground, working every day. He is fully committed to us and he will play on Sunday."
The Dutchman added: “I am convinced that he is playing for us on Sunday and I think it is so difficult in football to talk about what happens in a month or in six months. You can also ask me the question: ‘Are you convinced that Virgil [van Dijk] and Mo [Salah] are here next season?’
"It is such a difficult question to answer because there is hardly any long term in football, especially not for a manager, so your only focus is on the short term. The only thing I do know is that he [Alexander-Arnold] is fully focused and ready to play for us on Sunday and as long as he is here.”