A CONTROVERSIAL call because of the AFL's new rucking rule could change the dynamics around stoppages, Adelaide defender Luke Brown says.

Brown's teammate Dean Gore was struck by a boundary throw-in which fell short in Sunday's pre-season game against Geelong - and was penalised a free kick under the new rule banning a third-man up at the ruck contest.

Gore was watching the ruck battle rather than the flight of the ball - a tradition which may now change, Brown says.

"Maybe, that is something they (midfielders) have to do, keep their eye on the ball a bit more," Brown told reporters on Monday.

"And hopefully the boundary throw-in can be a bit further out, but I can't see that happening too many times during the year, to be honest.

"If they are going to pay free kicks like that, obviously you have to be a lot more aware of your surroundings and where the ball is going to land.

"... It has to be on the players to know where the ball is going to land as well."

Under the new rule only one nominated ruckman from each team can contest a stoppage - outlawing the tactic of a third player attempting to come over the top.

Crows coach Don Pyke expressed concern at the interpretation of the rule that cost his side, and Gore, a free kick.

"It's one of the real weird ones of that rule - if the ball hits you as a midfielder, and you're around the contest, it's a free kick against," Pyke said post-game.

"If that led to a goal ... I'd hate to see that happen in a big game.

"It seems like one of those things which is a bit of an anomaly, if you like. He wasn't trying to contest the ball - it was just that the ball hit him."