Garry Lyon hasn’t held back on his assessment of Jack Darling, saying the West Coast forward is “yet to prove that he can deliver”.

Darling’s performances in the last two finals series have been well documented, highlighted by a crucial dropped mark in the third quarter of the 2015 grand final loss to Hawthorn.

In last year’s elimination final exit to the Western Bulldogs in Perth, his decision to pull out of a marking contest in the second half also caused plenty of frustration among West Coast supporters.

The 226-game former Melbourne champion described Darling, 24, as a flat-track bully who needs to perform more consistently if the Eagles are to win important games on the road.

OPINION: Jack Darling is staying and West Coast fans have to deal with it

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“There’s a bloke called Jack Darling who is symptomatic of that football club, I’m putting heat fairly and squarely on his head,” Lyon said on Melbourne radio station SEN.

“He is a guy who can look like an absolute game winner at home and has struggled to replicate that in big games I’m talking about.

“He might kick four or five goals against the middle of the rung Tigers at the MCG, but on (the) big stage, big game away from home he is almost symptomatic of where they’re at.

“He’s yet to prove that he can deliver.”

Darling wasn’t the only Eagles player to cop a whack from Lyon, with Elliot Yeo also put under the microscope.

Play Video West Coast veteran Sam Mitchell chose to join the Ealges because they are on the cusp of AFL glory The West Australian Video West Coast veteran Sam Mitchell chose to join the Ealges because they are on the cusp of AFL glory

Lyon felt Yeo, 23, had gone “backwards” since his breakout season in 2015, but was hopeful four-time Hawthorn premiership hero Sam Mitchell’s arrival would help him reach his full potential.

“Elliot Yeo, this was a kid who was on the verge of exploding at the end of 2015,” Lyon said.

“When you make your assessment you go okay he’s going to elevate himself from a good player to a game changer, he went backwards.

“Maybe it’s the Mitchell factor that’s going to bring it out of these blokes, a bit like (fellow former Hawk Jordan) Lewis when he goes to Melbourne, they see a standard that has to be met week in and week out.

“That might be the real influence he has.”