Celtic assistant manager John Mjallby has confirmed that Gary Hooper, Georgios Samaras and Kris Commons will not play against Rennes.
The Bhoys return to Europa League action on Thursday with a trip to France, although manager Neil Lennon will be without a trio of potential options.
Hooper picked up an injury in Saturday's thrilling 3-3 draw at Kilmarnock while ex-Derby County playmaker Commons has tweaked his calf in training.
However, Mjallby is not worried by the attacking options the SPL side will be without as the Swede feels Lennon will have enough threats to cause problems for Rennes.
"Everyone is not fit," explained Mjallby. "Gary Hooper hobbled off at half-time (at Kilmarnock), he is not travelling.
"Georgios is unfortunately not with us and Kris picked up a calf injury in training and he is not travelling.
"But we still think we have a good number of players whose strength is in attack.
"Usually we are an attack-minded team so I'm not sure that we can sit back and defend, it is not in our nature, especially when we have been quite poor defensive-wise in recent weeks."
Celtic's SPL campaign has not gone as planned so far this season and Mjallby believes the European tie provides a welcome break mentally.
Lennon's troops have only won one of their last four in league action and Mjallby is hoping a possible win in Europe could kick-start things domestically.
"It is a good time," he continued. "It is a good break for us mentally.
"We know that we have to win every game and you are expected to do so, especially domestically, and we haven't had the best start to the season.
"We are fully aware of that and we are looking for improvements in all areas.
"So this is a good break for us, to try to find some form and inspiration to bring out in the league as well.
"We want to play the best teams in Europe and obviously we are in a tough group. It is a challenge for the players to show that this is a level that we want to be involved in."