All Blacks captain Richie McCaw believes Sonny Bill Williams would be mad to turn his back on the sport.
Williams has made his decision over his playing future for 2013, but is yet to make it public whether he'll stay with the NZRU or pursue a move back to the NRL with the Roosters.
McCaw says the Irish series proved Williams has made strides in the game.
"I think he showed that he can foot it in international rugby and makes a big impact there and to have a guy like that, along with Ma'a (Nonu) that can play at second five, having both of them being able to operate would be pretty special."
Richie McCaw says he hasn't spoken directly to Williams about staying.
Photo: Sonny Bill Williams (Photosport)