That revelation in his book Richie McCaw, the Open Side, shows sport's fine line and underlines the pressures of public scrutiny the All Blacks face in their everyday life.
It was that incessant attention which ate at Carter and in his dark days following the 2007 defeat he considered shifting his talents offshore. Not only him.
"I'm also aware that there's a core group of All Blacks we'll need in 2011 who haven't re-signed, and that if Dan goes, quite a few others might decide to go too," McCaw says.
"If I'm honest, it would knock me too, and make me think that maybe I should have a look at my options."
Those thoughts niggled McCaw before be broached the topic with Carter. He knew Carter's exit would reduce the All Blacks' impact significantly.
But McCaw's concerns were deflected when Carter assured him he was only thinking of a sabbatical and that he was keen on a third crack at the World Cup in New Zealand.
A year later after Carter's offshore sojourn is truncated because of his Achilles tendon injury, the All Blacks muddle through an even tougher patch.
It is a time when McCaw makes a rare admission that he feels the All Blacks are not as strong as he thought they were.
"Maybe, no matter what we do, we're not actually good enough," he thought.
During these difficult times, McCaw continued to pen his pre-test thoughts in his exercise book, a routine he continues as part of his pursuit of excellence.
He reveals some concerns and ideas about solutions in one excerpt from a troubled trip to Africa in 2009. He also notes his approach to referees.
"When ref is being inconsistent with his rulings. Especially when it is eliminating my effect," he writes.
"Be calm when I talk to him.
"Use right words - Can I speak with you a moment?
"Is that the standard for the game?
"Put pressure on him.
"Use short sentences which are to the point.
And later in the same self-instruction list McCaw writes:
"If they are putting one or two on me, must be opportunities for others.
"Talk to others (8,12,13) and get them to do my job.
and:
"Big guys coming, get low and use shoulder. Just need to be confident.
"NO FEAR."
That season was not the All Blacks' best but McCaw is still a champion. His jottings that year show what separates McCaw from others.
He is a machine with a mind, he has a body to cope with the brutality of the sport and an intelligence to unpick trends and adapt his game.