COLLINGWOOD forward Anthony Rocca is out of Sunday night's AFL blockbuster against Hawthorn after losing his tribunal challenge and being suspended for two games for rough conduct.

Rocca was found guilty of making negligent, high contact in his shepherd on Sydney's Sean Dempster at Telstra Stadium last Saturday night after the tribunal jury ruled the same way the match review panel did.

Rocca argued there was nothing more he could do to avoid making contact to Dempster's head, however the jury's verdict continued the AFL's crackdown on players who make contact to an opponent's head.

Rocca could have accepted a one-game penalty with an early guilty plea.

Collingwood have the option of launching an appeal, but Rocca, three Magpie officials and a two-man legal team left without making comment.

Rocca argued he did everything he could in applying a shepherd for teammate Alan Didak, in that he planted his feet and tucked his arm into his body and only made high contact because Dempster's body was leaning downwards at the point of impact.

That view was supported by field umpire Michael Vozzo, who had an unimpeded view of the clash but thought it did not warrant a report - only a free kick to the Swan - because Dempster's centre of gravity was lowered.

Vozzo said he was certain Rocca had done nothing wrong after viewing the incident on video.

Rocca argued he was within his rights to make a shepherd and would be "quite stupid" not to, and assume Didak had broken clear of his pursuer.

But he denied his bump was a heavy one, as he made contact with his bicep, and said his contact to Dempster's head was "purely accidental".

He said the Sydney defender should have been aware that a shepherd would come.

"If I wanted to I could have caused a lot of damage," Rocca said.

Dempster was treated for mild concussion, but returned after a short stint on the bench.

AFL legal counsel Andrew Tinney argued Rocca's contact was illegal and unnecessary, and that the tribunal had to uphold the league's view that a player's head was sacrosanct.

Rocca's suspension was his first since he was rubbed out of the 2003 grand final after being found guilty of striking Port Adelaide's Brendon Lade in that year's preliminary final.

The 29-year-old will miss matches against Hawthorn and St Kilda.