The Hungarian missed the Reds’ 2-2 draw against Manchester United in the Premier League on Sunday.
However, the no.8 should be back as they take on Tottenham in the League Cup this week.
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 squad rotation for Wednesday, he 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."