Just centimetres now separate a fair bump and an illegal one in the AFL, according to Western Bulldogs coach Brendan McCartney.
McCartney says most of his players have worked out what they need to do to remain within the rules, while acknowledging it was a difficult area.
The issue was brought to a head on Tuesday night when Geelong midfielder James Kelly was suspended by the AFL Tribunal for a hit on Essendon's Brendon Goddard.
A number of players, including Cats captain Joel Selwood, Hawthorn's Jarryd Roughead and even Goddard himself, strongly defended Kelly's action.
"It's pretty difficult for players sometimes to know how to position themselves," McCartney said.
"We're talking about one centimetre between being legal and a couple of centimetres and being illegal - it's a tough one."
McCartney - a former Geelong assistant coach - said he felt for Kelly yet also understood why he was suspended for two weeks.
Selwood tweeted on Tuesday night "the bump is dead" but McCartney said strong physical contact between players would remain a key element of the sport.
"All of us when we go to the football love to see fair collisions and people competing hard," McCartney said.
"There's a bit in all of us that loves a fair bump and that will probably stay in the game.
"But it is a grey area."
He said both the regulators and the players had difficult decisions to make.
"The game's played at frightening speed now and if someone slows down a little bit or turns their body a certain way or leaves a limb hanging out it can end up in someone getting a suspension.
"But the last thing you want is someone getting hurt so let the rule-makers keep adjudicating the game and we'll play it."
McCartney said his message to the Bulldogs players was clear.
"It's okay to run into other players and hit them but don't hang your elbows out," he said.
The Bulldogs, with just one win on the board, play the Gold Coast Suns on Sunday and McCartney said one of the main issues with the Dogs was completing each quarter.
He said players were fading in the last five minutes of each quarter but said the performance for around 80 per cent of the game was good.