Toni took no part in Sunday's training session due to a bruised ribs injury, which will most probably keep him on bench against his former club.
“We’ll take each day as it comes. Obviously, we’re hoping Luca will be fit to face Fiorentina as he’s totally fired up for the match,” Bayern boss Jürgen Klinsmann told the club's official website.
The Bavarians are currently top of group six with four points and Klinsmann stressed that the three points will put Bayern one step nearer to the next phase.
“The game is a huge chance for us to plant one foot firmly in the next round,” Klinsmann added.
“We’re really looking forward to the challenge, although we know it’ll be very tough."
Apart of Toni's injury, winger Franck Ribery and striker Miroslav Klose are both expected to recover from minor injuries to be ready for Tuesday's showdown.