National commitments have stripped Otago and Auckland of some their gamebreakers.
The Volts are without Brendon McCullum, Nathan McCullum, Neil Broom and Ian Butler, while Auckland will have to make do without captain Gareth Hopkins, Daryl Tuffey and Martin Guptill.
England international Ravi Bopara will also miss the match.
The batting all-rounder is being rested.
Otago had hoped Redmond would return to offset some of the losses but he is still labouring with the muscle strain he picked up while playing in a twenty/20 match against Pakistan in Abu Dhabi last year.
He has not played for Otago this season.
"He has been sorely missed, there is no doubt about that," Otago coach Mike Hesson said. "He's made really good progress but he is struggling with the last 20%. We were hopeful he might be right for this game."
Redmond scored 96 in a club game in late January but was not moving with a great deal of freedom, Hesson said.
"We know he can bat but he just can't move well enough. He's had some further tests and we are waiting to see how they come up."
There was some good news for Otago, with Wells returning from a shoulder injury.
He had an outstanding start to the Plunket Shield, picking up two five-wicket bags and scoring his maiden century.
While injuries are always unfortunate, his came just as he was starting to blossom on the first-class circuit and Otago will be hoping he can recapture that form quickly.
The one-day format has changed this year, with two fewer round-robin matches, but the play-off series has been expanded from three to four teams.
Otago is in last place with just one win from five matches and needs to win to get its campaign back on course.
"We are very much still in this competition. We are only one win away from fourth and we're certainly not out of the hunt," Hesson said.
While Auckland is without some of its stars, it still has an impressive line-up which includes Scott Styris and Lou Vincent.
Oamaru has not hosted elite cricket since Otago played Auckland in a one-day match in February 2005.
In recent seasons Centennial Park has failed to reach the standards required by New Zealand Cricket.
A twenty/20 match was pencilled in for last season but transferred to Dunedin.
The game is important for both sides.
Auckland's players will be looking to put the disappointment of the twenty/20 final loss against Central Districts behind them, and the Volts need the competition points.
Wells will be joined in the Otago 12 by top-order batsmen Shaun Haig, Leighton Morgan and Greg Todd, while for Auckland, Tim McIntosh, Andrew De Boorder, Bhupinder Singh and Lance Shaw get an opportunity.
Styris will captain Auckland in the absence of Hopkins.
Otago v Auckland
Hamilton, 7pm today
Otago: Shaun Haig, Leighton Morgan, Craig Cumming (c), Derek de Boorder, Darren Broom, Greg Todd, Sam Wells, Anthony Bullick, Yasir Arafat, Warren McSkimming, Neil Wagner, Nick Beard.
Auckland: Lou Vincent, Tim McIntosh, Andrew de Boorder, Scott Styris (c), Anaru Kitchen, Reece Young, Colin de Grandhomme, Roneel Hira, Lance Shaw, Michael Bates, Jimmy Neesham, Bhupinder Singh.
