Randy Carlyle is not a doctor, and he shouldn’t even play one on TV.

Not that the head coach of the Toronto Maple Leafs came across as anything other than a frustrated bench boss after the dispiriting 5-3 loss to the Philadelphia Flyers Thursday night, a loss more dispiriting because it included the image of Joffery Lupul, his best player, wobbling to the bench after taking a hard, twisting shot to the head early in the first period.

While Carlyle and the Leafs were calling it an “upper-body injury” and Carlyle said after the game that Lupul was feeling “fine” and it was “50-50” he would practise Friday, anyone watching the hit and Lupul’s wobbly reaction could safely call it like they saw it: the Leafs’ most snake-bitten player had likely suffered a concussion.

The study of concussions is still an evolving science but it’s gotten to the point that all 19,500 fans in the Air Canada Centre, the hundreds of thousands watching on television and every player on the Leafs bench likely made a better diagnosis of what had befallen their most prolific scorer in a key game during the Leafs’ most promising playoff drive in eight years than Carlyle did.

And if you don’t trust your eyes, trust an expert:

“That’s enough for me,” Dr. Charles Tator, project director of the Canadian Sports Concussion Project at the Krembil Neuroscience Centre at Toronto Western Hospital and one of the world’s leading experts on concussions said after watching the hit. “Wobbly legs on the way off after a hit like that that causes a player to go down? That equals concussion. I don’t think you have to be a genius to figure that one out.”

It’s a tough situation for the Leafs, Lupul, and for Carlyle.

Lupul is no Sidney Crosby, but with nine goals and 14 points in his last seven games — one of them in his 1:40 of action on Thursday — after missing 25 games with a broken forearm, he’s been an undeniable force on the ice and from all accounts equally as influential with his teammates off the ice as well.

Meanwhile the Leafs are in sixth place and poised to make some noise in an Eastern Conference playoff picture that features the Pittsburgh Penguins and perhaps the Boston Bruins as clear favourites but is otherwise wide open.

So the temptation to undersell Lupul’s injury from all sides — even by Lupul — is significant.

But even Friday the Leafs coach wouldn’t allow the possibility that Lupul suffered a concussion.

“No, that’s a bad word,” Carlyle said when he was asked if Lupul — who didn’t practise but hadn’t yet been ruled out of playing Saturday — had even shown symptoms of a brain injury. “We don’t use that word until we’re 100 per cent sure on any of the situations. The term concussion in today’s world, sporting world, you want to be 100 per cent sure before you start using that word.

“Until you know exactly what it is I don’t think you should make any statements. Everyone saw the hit, he got squeezed out, he was dazed and didn’t feel very good, so we sent him for an examination (Friday) morning and they just said he was day-to-day.”

Carlyle’s no expert, he’ll acknowledge.

“(As coaches) we’ve read medical journals that they’ve provided to get a better understanding of where the players are coming from, but we leave it to the player and our medical staff,” he said. “The coach has a player available to you when they say he’s good to go …. If it’s a bruised shoulder or a sore back or a concussion, we deal with them the same way. Until they tell us we have (the player) don’t dream.”

Has he ever suffered a concussion himself?

“The only time I really felt like I had that type of situation was in Montreal I got an elbow from Mario Tremblay and he broke a cosmetic bone in the side of my head and I went back to the hotel and I threw up and I was nauseous,” said Carlyle, who played 1,055 NHL games and never wore a helmet. “That’s the only time …if you can call that a concussion, I don’t know in today’s terms. But I played Wednesday.”

And?

“I didn’t do very well, no.”

But it’s not that Carlyle is without his views on the most unknowable of sports injuries, but they are theories based on personal experience — a school of thought that has its place but is consistently shown to be lacking when science enters into the equation.

He speculated Friday that the rise in concussions in the NHL and hockey generally may be tied to the universal use of head protection by the modern NHL player.

“I have a theory on concussions,” he said. “I think the reason there’s so much more of them — obviously the impact and the size of the equipment and the size of the player — but there’s another factor: everyone wears helmets, and under your skull when you have a helmet on, there’s a heat issue.

“Everyone sweats a lot more, the brain swells. The brain is closer to the skull. Think about it. Does it make sense? Common sense?” said Carlyle, who said he’d never talked to a doctor about his premise.

“I don’t know if it’s true, but that would be my theory. Heat expands and cold contracts. The brain is like a muscle, it’s pumping, it swells, it’s a lot closer to the outside of the skull.”

Again, common sense and current medical thinking on concussions aren’t on the same page.

“That wouldn’t be possible in my view — scientifically it is unsound to think that the temperature underneath the head and the helmet is going to reflect the temperature of the brain. There are too many layers of tissues in between,” Tator said. “The circulation of blood and other factors that dissipate temperature would prevent any outside change of temperature of a few degrees from getting the brain from getting into the brain. The theory doesn’t hold water — or you could say the theory doesn’t hold brain — scientifically.

“And I don’t think there’s any evidence that exercise makes the brain swell; I have not seen that.”

Lupul’s near-term future with the Leafs is far less certain, but one thing is clear: he’s better off with Carlyle as his coach, rather than his doctor.