South Africa's probable test top seven will include three lefthanders - opener Dean Elgar, JP Duminy and wicketkeeper Quinton de Kock - which enhances Patel's appeal.
But University Oval has been a strictly one-spinner assignment in its seven tests since 2008, for the likes of Dan Vettori, Bruce Martin and Santner.
Santner is a lock-in for the side, even if his batting needs to find another spoonful of starch. He keeps an end tight and his fielding adds value.
So picking Patel and Santner would fly in the face of recent history in Dunedin. More likely Patel will be in Dunedin just in case there's something in the pitch which pricks the interest of coach and captain.
Bustling Neil Wagner has won his race against the clock to be fit, after breaking a finger in a Ford Trophy game at the start of February.
He will be bursting to play against his former countrymen. Indeed, his numbers - 79 in his last 17 tests, 118 in 29 overall - demand his inclusion and he is forming a good, effective three-man seam attack with Trent Boult and Tim Southee.
Batsman Dean Brownlie and seamer Matt Henry have dropped out of the 13-man squad who prepared for the second Bangladesh test in Christchurch in January. It's the Plunket Shield day-night round next week for them.
Jimmy Neesham also returns but shapes as a strong candidate to be one of the two to sit the test out. He made 71 in his most recent test, in Indore in October, and has been in good touch in the ODI series. But with Henry Nicholls in at No5 and coming off a good series against Bangladesh - plus a 36, 76 double in his only previous test against South Africa, at Centurion last year - Neesham squares off against Colin de Grandhomme for the fourth seamer role.
Neesham's batting is better; de Grandhomme's handier with the ball, although his six for 41 on debut at Hagley Oval against Pakistan in November is taking on the appearance of a serious outlier. His last three tests have produced three wickets.
There's no place for Martin Guptill, as forecast yesterday, and that's fair enough, his blistering 180 not out in the fourth ODI at Hamilton on Wednesday notwithstanding.
He will be in the middle order when he returns to the Plunket Shield for Auckland. He should return to test cricket at some point. He's good enough, it's just about figuring out his best approach to test batting.
