The PSG star was left with a sprained right ankle after a crunching challenge in the French Cup final win over Saint Etienne on July 24.
"I've seen Kylian every day at the training centre, he's almost working 24 hours a day with the physios, but it's really short," said Tuchel on Wednesday.
"We've decided to assess with the doctor on Saturday to see if it's possible he could be on the bench against Atalanta, but I'm not expecting too much."
The World Cup-winning superstar's absence would be a huge blow to the Qatari-owned club who take on the Italians in Lisbon next Wednesday after claiming a domestic treble.
In another setback Tuchel could be without midfielder Marco Verratti, who has reportedly injured his calf in training, but on a more positive note he is hopeful "key player" Juan Bernat may play some part.