Jack Hunter led the way for the Volts with the white ball in the one-day competition but has been overlooked for one of the two remaining contracts.
Those spots have gone to all-rounder Christi Viljoen and top-order batsman Josh Tasman-Jones.
Volts coach Rob Walter is on leave but assistant coach Anton Roux said Hunter’s exclusion came down to the mix of the squad.
With former international all-rounder Jimmy Neesham transferring to Wellington, Viljoen was a better fit for the side, while Tasman-Jones would provide some much needed batting cover following the retirement of Rob Nicol and the departure of veteran wicketkeeper-batsman Derek de Boorder.
"Jack Hunter was the standout bowler for us in the one-day competition but he did not get too much of a go in the four-day or twenty20 comps," Roux said.
"The way New Zealand Cricket’s ranking system works is they get double points for the four-day competition and he just fell out of the rankings because of that."
Hunter took twice as many one-day wickets as anyone else in the Otago line-up. He bowled more overs and was the competition’s fourth-leading wicket-taker with a haul of 12 at an average of 22.75.
Given New Zealand Cricket has shifted its focus from the longer format to the shorter versions of the game, Hunter’s absence appears to be a hangover from an outmoded ranking system.
"Like you say it is a bit of a contradiction.
"With New Zealand Cricket this year opting to not play all 10 rounds of four day-cricket and basically flagging twenty20 as their key competition, it is, I suppose, a little disappointing. But you have to understand where they are coming from.
"They are clearly moving in a direction that is possibly away from red-ball cricket."
Tasman-Jones, who is new to the Otago contracts list, made his way down from Auckland three years ago and has mostly laboured away at club cricket level waiting for opportunities.
He has played two first-class games for Otago and a gutsy 59 not out against Northern Districts in Dunedin in March, 2017 underlined his potential.
"He has got the right attributes and the capabilities and hopefully he can deliver some results for us with more consistent opportunities."
Viljoen missed most of the season with a fractured ankle but he has done well in the past for the province.
He performs a similar role to Neesham in the team and, with all-rounder Anaru Kitchen focusing on limited-overs cricket, the Volts needed the cover.
Viljoen also bowls off the wrong foot and that can be confusing for the batsmen. He can also get prodigious swing in the right conditions.
