The England midfielder is said to be unhappy over his playing opportunities this season.
But Slot insists: "Since I am the manager he plays much more minutes than he ever did before. That's down to me liking the player and the fact our squad has become smaller, mainly because of injuries.
"That means the same players have to share the playing time because we went to the quarter-finals of the Champions League and the FA Cup. If you have a lot of injuries, then in the top 25 there are five or six players of ours with the most minutes played.
"Curtis played a good game against Everton, although now all of a sudden everybody had a good game because we won.
"I can tell you we played much better games when we have lost or drawn. But that's how football works - if we win then everybody played a great game, and if we lose then it's all s***."