Didier Drogba or Loic Remy will start up front for Chelsea when the Blues face Slovenian champions Maribor at Stamford Bridge on Tuesday.
Drogba has made one start since returning in the summer while Remy, has started two games.
But one of them could figure because Diego Costa, who has scored nine times, is out with a hamstring injury..
“When somebody is injured it as an opportunity for another player,” said Chelsea manager Mourinho.
Drogba, 36, shook off an ankle problem to come off the bench in the 2-1 win at crystal palace on Saturday.
Chelsea have four points from their opening two Champions League group games, while Maribor have two.
Mourinho’s side are away to Manchester United in the Premier League next Sunday but the Blues boss said he was only thinking about securing a victory over Maribor.
“I don’t have Manchester United in mind, I have Maribor in mind,” he said. “I don’t rest players. We must play with what we have, with the best we have.”