ADAM Simpson says "devastated" West Coast midfielder Andrew Gaff didn't intentionally hit Fremantle young gun Andy Brayshaw in the head in an incident that went "horribly wrong" during Sunday's tumultuous Western Derby. 

The Eagles are yet to decide if Gaff will travel to Melbourne to face the music at the AFL Tribunal in person on Tuesday evening, after his off-the-ball punch was graded as intentional conduct with severe impact by the Match Review Officer. 

Brayshaw's season is over after surgery to fix a broken jaw and displaced teeth, and Gaff's chances of playing again, even if the second-placed Eagles made it to the Grand Final, are in serious jeopardy.

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There were calls for his ban to fall in the range from six up to 12 weeks as the ugly fallout intensified on Monday.

While Simpson accepted there would be consequences for Gaff, the Eagles coach insisted his star onballer was trying to hit Brayshaw in the chest, not his head.

"Hand on heart, knowing Andrew and speaking to him post-game, he legitimately said to me he didn't mean to hit him in the head," Simpson told Channel Seven.

"We need to own the incident, and he did, and there's going to be consequences.

"But I think about 30 seconds before he hit him in the chest and I think he tried to do the same thing and he got it horribly wrong.

"Andrew's devastated, he's really disappointed in himself. He's let himself down and the club.

"But he's not the victim, of course, we know that. Our thoughts are with Andrew Brayshaw."

Gaff's brain fade has smeared his squeaky-clean reputation and could also cost him the chance to play in a premiership and win the Brownlow Medal. 

"I don't know why (Gaff hit Brayshaw). It was grossly out of character and something Andrew is very disappointed in," Simpson said.

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"There has been a lot of speculation and innuendo today. There's been a bit of trial by media, but we'll work through the Tribunal tomorrow.

"We need to own it, like we said, and make sure it doesn't happen again."

In a tense finish to the interview, Simpson was asked if there was a cultural problem at the club, with Gaff's Derby flashpoint coming in the wake of integrity officer Peter Staples' clash with cameramen at Perth Airport last month.

"I don’t think there's a cultural issue at the football club," Simpson said.

"I don't know what that's got to do with Andrew Gaff getting reported and taken to the Tribunal."