St Kilda's season is hanging by a thread, and its chances of making the Wildcard Round were hurt by the hamstring injury to superstar Nasiah Wanganeen-Milera in Sunday's loss to Carlton.
Early in the crucial contest, Wanganeen-Milera limped from the field after immediately grabbing at his left hamstring, with Saints coach labelling it "an arrow through the heart".
"I've had lots of stuff happen. Obviously, when it's 'Nas', it's sort of an arrow through the heart in a sense," Lyon said following the 44-point loss.
"I'm not sure what worst case (scenario) is, but I would think, what I saw, and I don't know much about hamstrings, (it's) minimum three weeks. He's not going to play in the home and away season.
"So, again, like Jack Silvagni, we're not taking a risk that isn't calculated and approved by a surgeon … It's a risk, and personal agency. I think it's a really good thing, and they make an informed decision, and that's what's happened."
Lyon was found scratching his head over the soft-tissue issue given the club's eight-day break between games.
“It's weird; we had an eight-day break. Played Saturday, Sunday and Monday off. Half day Tuesday, normal 3km run T1 (first training) on Wednesday. Thursday off, Friday our normal T2; they trained well. Saturday off," he added.
“It's not like we worked them. We're scratching our heads a little bit on the soft tissue.”
The Saints also had other injury concerns, losing utility Mason Wood to a calf injury.
Recruits Liam Ryan (left shoulder) and Tom De Koning (right shoulder) were also tended to by medical staff, as was co-captain Callum Wilkie (corkie).
"Look, it's not ideal really losing your best player, really. But in saying that, in this business, you've got to overcome it and not let it derail you," Lyon said.
"Regardless of that, I just think, 'How did the game look?' I thought their contest, pressure, really, they looked like the stronger team, pressure. Really simply, method coming in, we know how they're using the ball and controlling the ball."
