Well heck, they’ve brought back Jack and Audrey back from the why not?
We last saw Tony here:
“Tony learns that Henderson, the man who was responsible for Michelle, is now in the same room with him after the nerve gas lockdown. Tony grabs the guarding agent’s gun and threatens to kill Henderson. Jack talks him out of it over intercom. When Henderson lapses into a coma, Tony wants to inject him with a lethal dose of the medicine. Yet he can’t bring himself to do it. The alert Henderson takes Tony’s hand and forces him to stab himself. When Jack gets there, he finds that Henderson has escaped. Tony dies in Jack’s arms.”
I suppose it’s possible the injection he took wasn’t lethal. And since that was season 5, Jack, having been carted away to China, may not know that Tony’s alive, just as he didn’t know Audrey was . ha ha

how crazy that sounds!
Heck, we don’t even know if Curtis is really . We last saw him slumped next to the tire of the car and he had his vest on. I figured Jack shot for the neck but I didn’t see gushing out on his way down.
Where have you read/heard Tony’s back? Have they mentioned the Character name: Tony, or the actor’s name? On the Character files of the 24 website they have a **DECEASED **stamp over the character’s file photo.