Miller, who visited Polak in hospital again on Tuesday afternoon, was uplifted to see the 24-year-old walking, greeting people and contributing to conversations.
Polak was moved out of intensive care on Monday night, less than 48 hours after he was hit by a tram when crossing the intersection of Orrong and Dandenong roads near his Armadale home.
"To see the progress he's made in such a short time is testament to his fitness, testament to the staff at the hospital and also to God's wishes," Miller said.
"He's certainly progressed very quickly in what could have been far worse ramifications."
Miller also acknowledged the strength of Polak's family throughout the ordeal, with his mother, three brothers and aunt joined by his girlfriend's parents, her sister and partner.
"To see the strength of the family ... there were times there, particularly Sunday night, where mixed messages were coming from the nurses who were looking after him," he said.
"Some of those messages were upsetting but other members of the family helped them through it.
"I've just been there more as assistance to the family, just to make sure they had things that they needed from the club and what the club could do to help.
"Everyone together behind the scenes, Kayne Pettifer and Chris Newman, we've tried to limit the players' involvement because it's just too much. But (Pettifer and Newman) have been by his side as well.
"It's been uplifting to see his progress."
Miller added that young Tiger Cleve Hughes, who was with Polak and teammate Jordan McMahon when the accident occurred, would also be making a visit.
"Cleve's on his way down," he said. "We want Cleve to go and see the progress because we think that will be a great tonic for Cleve.
"And I spoke to Jordan, and he's buoyed by every message that he receives about the progress, making things easy for him as he knows Graham's moving out of the danger zone.
"We've kept [all] the players informed every step along the way and they also are very keen to see him. As each hour goes by or each few hours go by, he can handle a little bit more but we don't want to overload him either.
"It's been remarkable. You see so many tragic stories and to see what could have been tragic, the progress so far's been great."
