Again pure speculation, but the coaching staff may well have been part of the issue.
Players and coaches always want to win and for some reason they see round one as being a really important game. I'll be honest and say I don't know much about the high performance team at the moment but as
@caesar said a loss of experience can make you vulnerable.
It is a really lonely place to be when a player wants to play and the coach wants him back and you are saying no. It really takes a hard edge that only experience can bring you. I know in my personal experience AFL was the most challenging environment I ever managed athletes in, the pressure and the scrutiny make it very difficult. I was coming from a place of having 20 plus years of experience, I'd had Australian cricketers threaten to bash me for not letting them bat, or not talk to me for 5 days on tour because they were ruled out of a game, or be fronted by wives or girlfriends to hand out a spray. If it is your first time dealing with those types of passions it is bloody hard and mistakes will be made.