Astle has overtaken Tarun Nethula, who developed a case of the yips on the recent tours of the West Indies and India, and has the chance to cement a place in the New Zealand side under new coach Mike Hesson. They will need two spinners for the tests against Sri Lanka and Astle seems assured of a spot given he and Jeetan Patel are the only ones touring in the absence of the injured Daniel Vettori and axed Nethula.
It would help if he can continue his form with the bat. Canterbury were in all sorts of trouble against Otago today after winning the toss and electing to bat, slumping to 153-7.
Astle clubbed 13 fours and one six in his 106-ball innings and found great support from Ben McCord (17) and Willie Lonsdale (35) to ensure Canterbury posted a decent total.
Astle looked set to bring up his second first-class century only to be bowled by McMillan soon after Otago took the new ball.
"He played aggressively and took the game back to Otago a bit, which was fortunate for us," Canterbury coach Gary Stead said. "He's a great kid and is always willing to put in the hours at training to become a very good leg spinner and batsman.
"He will probably be the first to admit his batting hasn't always hit the mark but all I have asked him to do is go out and play positively and today he showed what he is capable of."
Test cricket will be a significant step up but there are few better places to learn than Sri Lanka and, if New Zealand can secure the help of Muttiah Muralitharan as a spin coach for the tour, few better people to learn off.