O'Keefe has played just one test, taking four wickets in Sharjah in a loss to Pakistan last year.
He's rated handy but the fact that he's not been close to nudging regular spin pick Nathan Lyon aside indicates his place in the pecking order.
Pattinson is the most interesting selection.
He ripped the top off New Zealand's innings on debut in Brisbane in 2011.
Injuries have hampered the big Victorian quick. However in two Sheffield Shield games this season, he's taken eight wickets; and he snared 14 in seven Matador Cup 50-over games at 19 apiece.
The expectation is that veteran Peter Siddle will come in for Johnson, but the question mark sits over Josh Hazlewood, who made little impact on the flat pitch in Perth in the second test.
Australian officials are concerned about too much bowling for the faster bowlers, with another three tests to come against the West Indies.
Hazlewood may sit this test out, giving Pattinson a chance to press himself back into the frontline.
''The make-up of the side is key for us. Two spinners or three quicks, we'll have to wait and see," coach Darren Lehmann said.
''They're all a bit sore, so we'll wait until we get to Adelaide."
The point about the changes is that New Zealand should be reasonably relaxed about them.
Marsh is a known quantity; O'Keefe is unlikely to figure for all Lehmann's talk of an open mind; and Pattinson has form against them, and is well rated. But he's no Mitchell, Johnson or Starc.
In fact tall left armer Starc may occupy much of New Zealand's focus once they get to Adelaide.
His record with the white ball is formidable - and the pink ball is uniformly regarded as far closer in behaviour to the white than the traditional test red.
