Sidney Crosby skated with the Penguins on Saturday after missing Game 6 against the Rangers.
The Penguins say he suffered an upper-body injury in Game 5 against the Rangers on Wednesday.
Crosby didn't wear a non-contact jersey during the optional practise, but Sullivan wouldn't say if he's cleared for contact.
Crosby skated individually with Ty Hennes on Friday.
Crosby had nine points against the Rangers in five games.
Also resurfacing Tristan Jarry, the starter, hasn't played in this series due to injury, and Rickard Rakell hasn't played since Game 1 due to a concussion.
All players will travel to New York for Sunday's Game 7, Sullivan said.