Campbell is ahead of schedule in returning to first-team action for the Black Cats.
Campbell has been out of action since April due to a second cruciate ligament injury.
“Fraizer is just remarkable,” Bruce told the Daily Mirror.
“We hope that by Christmas he can be involved in the first team again. It’s a quite remarkable achievement.
“It’s testament to all the hard work he’s done. If you’d seen the running he’s doing, you’d just say ‘Wow’.
“He’s had two cruciate injuries, but he looks brand new and full of life. There’s no sign of any limp or any deficiency.
“Mentally, he’s had to be really strong. At the time of his injury, he’d had a wonderful pre-season and scored four against Hull.
“He was the main striker, playing as well as anybody here, and he’s been a miss.”
