Marchisio admitted that he is always looking to play but will listen to the advice of club doctors if they say he is not "100%" for Sunday's match.
"I am quite fit; I have trained for two days, but I do not know when I come back," Gazzetta dello Sport quotes him as saying.
"The next 48 hours will be decisive to see whether I play against Fiorentina or Celtic. We still have a few days to evaluate how I am, but I always want to play and there is also risk when you are not 100%."
Marchisio has scored five goals in 27 appearances for Juventus this season.