He said the report of O'Brien should act as a test case for how the rule will be interpreted.
"I wish it wasn't one of our players that is getting tested, but it is a test case," Buckley said after Collingwood's 55-point loss to Hawthorn at the MCG.
O'Brien was reported for rough conduct in the second quarter despite Hodge sliding into the Magpie, who kept his feet. Hodge received a free kick in the incident.
After the game, Hawthorn coach Alastair Clarkson expressed surprise that O'Brien had been reported.
His response demonstrated the uncertainty among clubs as to how the rule is being interpreted.
"He's been reported? Has he? I didn't realise that. That's a bit harsh. I'd need to look at the tape to make a judgement," Clarkson said.
Buckley said that whatever the AFL Match Review Panel decides in relation to O'Brien, he hopes the outcome will make it clearer to players what they can and can't do.
He said O'Brien could easily have won a free kick but instead found himself on report.
"Harry was doing what he is required to do in that situation," Buckley said.
Clarkson said adjudicating the rule in slippery conditions was a potential minefield for umpires and Buckley was careful to not be critical of anyone. He was happy to see how it played out.
"That will take its course during the week and whatever way it goes we certainly hope that it is clearer for the players," Buckley said.
