He clubbed 96 off 67 balls against Otago in a Ford Trophy game at Invercargill on February 1, then cracked 74 from 50 balls and 82 off 63 - nine sixes altogether - to help Wellington beat Canterbury by five wickets at Rangiora in the Plunket Shield yesterday.
"Our medical staff have given him a thorough once over, and they've given him a tick," national selection manager Kim Littlejohn said last night.
"We're as sure as we can be that he's ready to go."
The final composition of the side for tomorrow night rested with coach John Wright and captain Brendon McCullum.
Fingers will be crossed that Ryder stays free of injury for the remainder of the South African tour.
With captain Ross Taylor out of the ODIs as he recovers from a torn calf muscle, Ryder adds considerable substance to the batting contingent.
Canterbury batsman Dean Brownlie is touch and go for the start of the tests as well, after fracturing a finger against Zimbabwe at Whangarei on February 6.
A fully fit and firing Ryder looms as crucial for the start of the test series at Dunedin on March 7.
The 14 players for the ODI series were named yesterday, with no major surprises.
Canterbury teenager Tom Latham was left out. He made an encouraging start against Zimbabwe but this is South Africa and the prevailing view was the pragmatic one.
"One train of thought was to throw him in the deep end and see if he swims. But we believe he's a special talent and want to ease him into it," Littlejohn said. "We felt it was too big a jump to throw him in against South Africa, given they're fighting for the No1 spot in the world."
The lively left-armer Andy McKay is back on the strength of a strong domestic season for Wellington, in which he topped the national 50-over figures with 18 wickets at 18.05, and snared 12 HRV Cup wickets at 19.83.
McKay against fellow left-armer Michael Bates looms as something of a head-to-head contest for the fast-medium lefty job.
James Franklin's T20 form made it near-impossible to leave him out while Tarun Nethula's leg spin impressed sufficiently against Zimbabwe for him to get another opportunity against stiffer opposition.
The calf strain picked up by Jacob Oram against Zimbabwe has ruled him out of the series.
As for the South Africans, the heavy mob arrived for the ODI series on Sunday.
Test captain Graeme Smith, premier fast bowler Dale Steyn and allround great Jacques Kallis have pitched up, having missed the T20 series.
As if things weren't warming up on tour with the T20 decider tomorrow night, their arrival means the ante is about to be ramped up a further notch.
ODI SERIES
New Zealand ODI squad:
Brendon McCullum (c), Martin Guptill, Rob Nicol, Kane Williamson, Jesse Ryder, James Franklin, Nathan McCullum, Doug Bracewell, Andrew Ellis, Tarun Nethula, Kyle Mills, Tim Southee, Andy McKay, Michael Bates.
Schedule:
* Saturday: First ODI, Westpac Stadium, Wellington.
* Wednesday: Second ODI, McLean Park, Napier.
* March 3: Third ODI, Eden Park.
