FREMANTLE coach Ross Lyon says he had to calm his players down after they wanted retribution following West Coast onballer Andrew Gaff's off-the-ball strike on Dockers young gun Andrew Brayshaw.

Lyon was emotional during his post-match press conference on Sunday, describing the scenes in the rooms as Brayshaw's mother, Debbie, broke down in tears.

TEMPERS FLARE, EAGLES SOAR Full match coverage and stats 

Brayshaw will undergo surgery on Sunday night to repair a broken jaw, with his season almost certainly over after the incident roughly 20m off the play during the third quarter.

"Andrew Brayshaw was king-hit 100m off the ball. He's got a fractured jaw and four displaced teeth that are caved in, and he'll be undergoing surgery tonight," Lyon said post-match.

DEMOLITION DERBY 2.0 Five talking points

"I think it's self-evident (what my thoughts on the incident are). I've got an 18-year-old kid that I saw in a real mess when I came down to the rooms and his mum in tears as I was walking in.  

"It's not very palatable. 

"He was pretty distraught. I gave him a hug. It's hard to keep the emotion back yourself. To see his mum, it's pretty tough. 

"It's a tough enough business as it is. It's a pretty significant moment I would've thought. Our No.2 pick won't play again this year, I wouldn't have thought."

WATCH Gaff's hit sparks Derby chaos 

Tensions threatened to boil over after the incident in the Dockers' 58-point loss, which saw Brayshaw taken to hospital in an ambulance. 

"It's very distressing. My senior players certainly wanted retribution and I had to stay out on the ground longer at three-quarter time to settle a couple down and say, 'don't bring yourself into disrepute'," Lyon said.

Asked if he was angry, Lyon replied: "Am I angry? I don't know. I'm pretty emotional. It's a tough enough game," he said.  

"I wouldn't have liked to have seen my son like that."

Lyon wouldn't be drawn on how severe Gaff's sanction should be, but compared the incident to the infamous Barry Hall punch on Brent Staker in round four, 2008.  

"I'm just putting the facts forward. Andrew is unlikely to play again this year. There's certainly precedents set. I think Barry Hall got seven (weeks)," he said.

WATCH Ross Lyon's full post-match media conference

Gaff's strike overshadowed a seventh-straight Western Derby defeat for the Dockers, who shot themselves in the foot with some disastrous ball use.

"I thought we started the game really well with plenty of entries (inside 50) but inefficiencies," Lyon said.  

"At the end of the day, hopefully we'll go forward and be able to play with more polish. Do the basics better.

"There were some dropped marks, missed handballs and fumbles that were really costly, but we fixed our centre square bounce work from the week before." 

The Dockers have now lost five of their past six games since the mid-season bye but have a chance to equal their eight wins from last year against bottom-placed Carlton next Sunday.  

Freo is unlikely to regain key defender Joel Hamling for the clash, after he hurt his calf at training this week.

Injury-prone star Stephen Hill, who has battled numerous soft-tissue problems this season, also "tightened up" late in the clash and will be assessed this week.