Hansen said of Faumuina: "Charlie is someone we've been sweating on because he's a big part of our team. If he comes off the bench he is a real dynamic tighthead, we saw that in the England game when he came on in November last year. He's a good scrummager, a good ball carrier, he's been battling to get game time and getting knocked out didn't help. Thankfully he recovered quickly from that, the medical process was great. He's confident and now we've just got to get him match fit."
Faumuina's surgery to release a nerve compressed by a bulging disc was necessary because he was losing strength in his left arm.
That strength has yet to fully return, but he showed in his performance for Auckland that he has lost few of his skills during his lay-off, and even his conditioning wasn't bad considering.
"I had my doubts [at being selected for World Cup], especially with the surgery, but after the surgery, just coming back and seeing the medical team, they confirmed it was successful and I couldn't harm it any more.
"It has been frustrating, especially with the knee surgery and then ... getting the concussion slowed things down a little bit."
His confidence in the scrums and at the tackle has been slowly returning and that would have been increased after the All Blacks' first World Cup training session in Wellington today.
It was a physical session which for Faumuina was compounded by the aches and pains of a recent first match in several months.
He is readying himself for more conditioning sessions with All Blacks trainer Nic Gill, plus more time on a neck harness contraption which looks like something out of a medieval dungeon.
Faumuina said: "You see people looking at you funny but it's something you have to do to make sure the neck is good and strong."
