Tottenham forward Heung-min Son will serve the first of a three-match ban for today's Premier League clash against Brighton, opening the door for one of Christian Eriksen, Giovani Lo Celso or Ryan Sessegnon.
The Dane, a half-time substitute against Chelsea, seems likeliest to get the nod.
Spurs lodged an appeal against Son's ban, but the decision was upheld so Son will be absent against Brighton, Norwich and Southampton over the festive period.
"We don't have a big squad," Mourinho said. "We don't have lots of players.
"This moment is a moment where it is normal to think about rotations and very difficult situations for players to play every game.
"We don't have (Erik) Lamela and it's a big loss for us. But if that happens then we have to try to cope with it and to fight against injustice.
"But the way to fight against injustice is to give our best and the boys that are going to play are going to try and get results in it."
Lamela is back in training after two months out with a hamstring injury, but Mourinho said he will not be fit enough to be involved against the Seagulls.
Eric Dier, who gave way for Eriksen, is likely to be able to continue but Jose Mourinho could bring Tanguy Ndombele or Harry Winks back into the side, while Moussa Sissoko and Lucas Moura will battle it out for a place in the front three.
Elsewhere, Danny Rose could replace Jan Vertonghen in the back four, with another game against Norwich on the 28th.
Predicted Tottenham XI (4-2-3-1): Gazzaniga; Aurier, Alderweireld, Sanchez, Rose; Ndombele, Dier; Sissoko, Alli, Eriksen; Kane.
