Tighthead prop John Afoa was a little miffed when the phone rang in the middle of his Sunday morning cartoon-watching schedule.

It was All Black scrum doctor Mike Cron, suggesting the prop come in for some remedial work on his game. The cartoons could wait as Afoa sensed the importance of the offer and headed for the All Black hotel.

"Mike gave me a little nudge saying 'You're in but act surprised when Ted [Graham Henry] tells you," Afoa said yesterday as he talked through his shock All Black selection.

The 21-year-old has succeeded Canterbury tighthead Campbell Johnstone in the squad picked for Tri-Nations duty in South Africa and Australia.

The rationale was quite simple, according to Cron and the All Blacks panel.

Johnstone had missed half of the Super 12 because he pulled a muscle in his chest but he had been identified as someone with a strong technique and potential. He had been included in the squad to face the Lions to refine his skills.

Now he needed to get more matchplay in the NPC rather than clocking the kilometres with the All Blacks on the training field.

Afoa was the reverse. He had played an enormous amount of rugby in the Super 12 for the Blues and had shown out for the Junior All Blacks and Auckland against the Lions.

However his technique needed some attention and the offshore leg of the Tri-Nations was an ideal time for the coaching staff to give him some intensive instruction.

"He got a hurry-up from Tony Woodcock in the All Black trial and we need to just look at a few things and sort them out," Cron said yesterday.

Afoa is part of a growing wealth of frontrow talent in Auckland with fellow All Blacks Tony Woodcock, Saimone Taumoepeau, Keven Mealamu and Derren Witcombe.

Afoa first played for Auckland as a teenager against Counties Manukau in 2002 and took over the role this year as the main tighthead prop for the Blues when Kees Meeuws left for France.

After switching from Pukekohe High School, Afoa joined Joe Rokocoko and Jerome Kaino as stars in the St Kentigern College 1st XV before they began their progression through age-group teams.

"I didn't even know the difference [between loosehead and tighthead props] at schoolboy level," Afoa recalled.

Since then the 126kg, 1.83m prop has shown his aptitude with his scrummaging, agility and great speed for a man of his size. He credited the Junior All Blacks tour for his national recognition.