The 20-year-old had performed solidly against Essendon last Sunday after coming on as the sub, but the return of stars Chris Mayne and Nat Fyfe saw Simpson named as an emergency for the SCG clash.
He was supposed to travel with the team to Sydney but never turned up to Perth Airport.
Lyon said Simpson had endured a difficult adjustment to AFL life since being drafted with the club’s first selection in the 2012 National Draft.
“He has had a number of family, cultural and attitudinal situations to work through,” the senior coach said.
“He’d done enough to be picked, but in this case Josh was clearly disappointed about being out of the team, so he’s basically dropped his bundle.
“That’s what’s occurred there.”
Lyon said the club was mindful of the pressures Simpson, who hails from a remote Indigenous community called Yalgoo, 500km north-west of Perth, faced as an AFL player.
The senior coach said Simpson had gone back home before for various reasons during his AFL career, ranging from family illnesses to western medicine versus traditional medicine, and he added the young forward also had two children.
“There’s a lot of pressures there,” Lyon said.
“He hasn’t walked out of Hale School with a silver spoon in his mouth. He’s been through some trying circumstances in his life.
“Therefore, we’re trying to build a base and nurture and work with Josh and counsel him, and also at times discipline and encourage Josh to be able to handle the rigours of AFL football.”
Lyon revealed Simpson had returned home during the week because of cultural reasons.
The Freo senior coach said Simpson’s circumstances were also trying on the football club.
“Sometimes, you’re trying to do what the education system, families, mentors, elders and the government can’t quite do,” Lyon said.
“We’re working through all those things with Josh.
“In this particular instance, it’s been an attitudinal, ‘taking your bat and ball and going home’.”
Despite Simpson’s issues, Lyon said he had not run out of patience and added the club would continue to support the player through this difficult period in his life.
“We’re here to support the person and challenge the action or the behaviour,” he said.
“In this situation, we’ll clearly come together as a football club; leaders, and with Josh and his manager, and talk about potential ramifications and what it means and how he needs to earn the trust back.
“No one will leave our football club without being fully supported, fully resourced and given every opportunity.
“If you end up not being with our football club, you’ve chosen that in the end, so let’s hope we don’t get to that point.”
