The two January signings have not been included in the 25-man squad registered by Celtic with Uefa for the knockout rounds of the competition.
Clubs were entitled to make three changes from the original list posted for the Group Stage games, and both midfielder Rogic and defender Gershon hoped they would be included.
But, after assessing the condition of both players, Neil Lennon has decided neither will be ready to face the Italians in the last 16, the first leg of which is at Celtic Park a week tomorrow.
Efe Ambrose will not return from Africa Cup of Nations duty until after next weekend following Nigeria's victory over the Ivory Coast yesterday put the Super Eagles into a semi-final against Mali on Wednesday.
And, with a third-and fourth-place play-off and the final scheduled for next Saturday and Sunday, the defender will face a race against time to be back in Glasgow to show Lennon he is ready to face Juve.
Despite this, Gershon has not been drafted in as a possible replacement as he is struggling to recover from a groin injury picked up in one of his first training sessions with the club he joined on loan from Standard Liege.
Rogic has also been omitted from the squad as Lennon believes it would be unrealistic to expect him to be up to the required fitness level in time.
Following the delays caused by obtaining the necessary paperwork, the 20-year-old will only pull on a Hoops shirt for the first time tonight in a reserve game.
Lennon confirmed keeper Viktor Noring's loan transfer from Trollesborgs has been completed. But, he too, has been left out of the Champions League list.
The Hoops will again go with just Fraser Forster – who is expected to return to action at Inverness this weekend – and Lukas Zaluska.
The manager explained why he has elected not to utilise any of the changes available to him.
"Tom is not in the Champions League squad because it is too early for him," said Lennon. "He will have a reserve game tonight, against Hamilton at Firhill.
"But, with a week-to-10-days preparation, he is not ready for Juventus just yet. I couldn't put Tom straight into the squad."
On Gershon, Lennon said: "Rami is not fit, and has not been for the past two weeks. The game is a week tomorrow. I can only pick so many players, and I want them all fit and ready to play.
"Rami has a groin problem, which he has had since he came back from Marbella. He has had an injection and we are hoping he will start training again this week."
Juventus have added Nicolas Anelka to their Champions League squad, but the striker was an unused sub yesterday as they moved three points clear in Serie A with a 2-1 win away to Chievo, their goals coming in the first half from Alessandro Matri and Stefan Lichtsteiner.