The 24-year-old, who is in the club’s leadership group, was subbed out of last week’s game against North Melbourne.
He was not originally named in the 25-man squad to play West Coast, but a hamstring injury to Stephen Hill has led to de Boer being put back in the squad.
Injured Hill to miss Derby clash
Lyon said de Boer’s recent performances, coupled with the strong form of other players, were factors in him not being picked at selection.
“It’s little bit of form,” he said in his morning media conference.
“He was quite good in the first three or four rounds, but he’s tailed off in the past couple of weeks.
“And just on balance, we thought (Hayden) Crozier was terrific for a young player.
“We’ve had a good chat to Matthew and he responded well. He just wasn’t at his best.”
Lyon said the club held its leaders to higher account and he was confident de Boer would respond immediately.
“(We expect him to) work really hard, win the ball, use it well and just show strong leadership and enthusiasm, which are typical traits of Matthew’s,” Lyon said.
“He’s been a successful player because he prepares really well and gives his all.
“That’s what we’re looking to see.”
