Melbourne were puzzled as to how defender Harrison Petty became concussed, with scenes on Sunday at the MCG causing for concern.
Nearing the end of the third term, Petty was dazed, and rang alarm bells after a turnover from a kickout before putting his hands on his knees before seeking the ground for stability and support.
He was met with teammates and trainers, before being pulled from the ground, with vision showing Petty saying: "I'm dizzy".
"We're still having a bit of a look at that, potentially concussion or something," Demons coach Steven King said, after the two-point win over Brisbane.
"We'll do all the right tests but we're not 100 per cent sure, but he was complaining of some blurred vision so we'll do all the test tonight and tomorrow. Obviously, not great.
"I think it's something he received that ball in the goal square and he probably thought ‘I should've stopped the game'.
Harrison Petty has come from the ground in the hands of the trainers.#AFLDeesLions pic.twitter.com/cCOk27vazQ
— 7AFL (@7AFL) April 19, 2026
"Whether it was something more sinister, whether it was delayed concussion, we'll have a look at it.
"I think he mentioned something (about blurred vision) before, slightly before that kick, we're obviously going to take it pretty seriously."
Melbourne GM of Football Alan Richardson said the club was "bemused" by the instance.
"He's certainly got symptoms of concussion. We're a little bit bemused as to how ... whether it was delayed concussion. There was nothing in (any prior) incident that led to him going off the ground, so we assume it must have been a knock he got earlier," Richardson said.
"Our docs will have a look back at that."
Unfortunately, Petty wasn't the only injury concern, with the reigning premiers facing a pair of problems in the shock loss.
Jarrod Berry was ruled out during the second term with a calf injury. He joined defender Noah Answerth, who suffered another concussion upon his return game from a head knock he sustained in Round 3.
"I didn't see it. I was a little bit surprised when he came off and they told me that he was in the protocols," Fagan said.
"He's had a few concussions. So we're in the lap of the gods on that one. The main thing is what's good for his health."
Fagan wasn't sure whether it could be another extended break for Answerth, given his history with concussion.
"I don't know," he said.
"It'll all depend how he responds, I guess ... the AFL can ask for extra tests and things like that, so I don't know whether Noah will become one of those people that go into that category or not, so we'll just have to wait and see on that."
