The midfielder was forced to miss the 2-2 draw with Manchester United in the Premier League last weekend due to illness.
Asked if he is expecting to have the No.8 available for the trip to Spurs, Slot told a press conference on Tuesday morning: "Yesterday he wasn't in yet. If he's in today, I would doubt if he's available to start the game.
"But hopefully he's in today. Yesterday he wasn't."
On the possibility of rotating his squad for the trip to Spurs, the head coach added: "I think if you look at all the fixtures we've had this season, there are so many things going into a line-up – short term, long term, qualities of the opponent, where are my players [at]?
"So it's going to always be a decision made about, in our opinion, the best line-up for tomorrow. In some situations, for Southampton away or other games, in my opinion the best line-up was the ones that didn't start a lot.
"Let's see what that is tomorrow for the game we play against Tottenham."
