Wallabies flanker David Pocock has again shown why he is the class act of international rugby.

Rather than chasing play, Pocock went to the aid of All Black Ryan Crotty immediately after the centre was floored by a hit to the head by his team mate Jack Goodhue early in the Bledisloe Cup opener.

As play continued at ANZ Stadium in Sydney on Saturday night, Australia No 8 Pocock's priority was to check on the wellbeing of Crotty who was felled by friendly fire as the two New Zealand midfielders went in for a tackle.

GETTY A dazed Ryan Crotty is helped off the field in Sydney after his latest head injury.

It was Crotty's sixth concussion in the last 18 months and worries swirl around the likeable Cantabrian.

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Pocock's unselfish actions earned high praise from All Blacks flanker Sam Cane, a player who has also had his share of concussion issues.

"It speaks pretty highly of his character and the type of guy he is if he's willing to put the battle to one side in that moment and put the player's welfare first," said Sam Cane, the All Blacks openside flanker and Pocock's chief breakdown rival.

"So, thank you David."

Pocock, on the comeback trial to international rugby, has made stances over human rights, environmental and animal welfare issues and is acknowledged as one of the nicest guys in the game – as one of the most competitive in his combative back row position.

Crotty has been ruled out of the rematch with the Wallabies in Auckland on Saturday night though medical checks after the match suggest he will be OK for involvement in the Rugby Championship further down the line.

"It concerns us, definitely," said All Blacks coach Steve Hansen of Crotty's ongoing issues. "He's already seen a specialist and they've given him the all-clear. From our understanding as long as you fully recover and don't go back when you're not fully recovered, then you're OK.

Cane was worried too for his team mate in the 38-13 win in the Bledisloe Cup opener.

"It's not nice to see," Cane said of Crotty lying prone on the field and then being assisted off in a groggy state.

"It's just a tough injury.

"Everything else has a time frame but there's just so much unknown with head knocks and it seems like you can be only one away, if it's the wrong one, from it being then end of it.

"I've seen that with a few mates.

"It certainly helps you appreciate every week and every game you have and realising how fickle it can be."