Gomez has been absent from the Reds’ matchday squad since being withdrawn during last month’s defeat at AFC Bournemouth because of an injury.
However, the defender could be available to return for Wednesday’s clash at the Stadium of Light (8.15pm GMT kick-off).
“Joe has not trained with us yet,” Slot told his pre-match press conference at the AXA Training Centre on Tuesday morning.
“I’m expecting him to train with us for the first time today. Indeed, if Joe is not ready to start then we are missing four players who have played in that position.
“But Curtis [Jones] and Wata [Endo] also played in that position this year, so we’ve had six different right full-backs this season.”