Black Caps Mark Craig, Hamish Rutherford and Neil Wagner bolster the Otago side significantly but that has not translated into better form.
The Volts won three of their first four games without Rutherford or Craig but have lost two of their past three games with them in the team.
Wagner returned a game early and helped Otago beat Northern Districts.
That was Otago's most recent win.
The Volts were comfortably placed then but now have to beat Canterbury in Rangiora today to secure a home venue for the minor semifinal.
A loss could spell the end of the campaign although the Volts could still limp into the playoffs depending on other results.
''We've been in this position before and managed to fight our way back,'' Wagner said.
''Every game now is a final for us. We know we have to win so for us it is just about staying positive when we get into positions like we did the other day.''
Wagner bowled a tremendous spell into the wind during the four-wicket loss to Central Districts at the University Oval on Sunday.
He picked up two wickets for three runs in his opening four-over spell. And Jacob Duffy bowled with some serious heat with the wind at his back.
Central collapsed to 11 for three, but Kruger van Wyk played a marvellous innings, stroking a maiden one-day hundred to guide his side a fabulous win.
It was gut blow for Otago who had got into a position to win the match but could not close out the game.
''Kruger batted really well ... but I don't think we bowled very smart at times,'' Wagner said.
''I think we should have tried to go for the kill more and been more ruthless. We let it slip.''
Otago has made two changes to the side which lost to Central. Left-armer Craig Smith replaces batsman Iain Robertson in the squad and all-rounder James Neesham joins the group.
Neesham has been struggling with a back injury and will need to pass a fitness test this morning to be considered for the playing XI.
Canterbury has a familiar look. Black Caps seamer Matt Henry rejoins the team at the expense of wicketkeeper Freddie Anderson.
Canterbury smacked 356 for three and beat Wellington by 85 runs at the Basin Reserve on Sunday.
Opener Henry Nicholls whacked a Canterbury record 178 and featured in a New Zealand record second-wicket partnership of 291 with Neil Broom (117).
''They are a dangerous team. They are alway there are thereabouts. They've got good players and obviously some experience too.''
Otago coach Dimitri Mascarenhas agreed with Wagner's assessment.
''Canterbury are playing well and fighting for their season so we are well aware of the challenge they will provide,'' he said.
''The future of our campaign is still in our own hands and that's the way we want it to remain. The boys are treating this game effectively as a quarterfinal and have trained really well.''
Otago v Canterbury
Rangiora, 11am today
Otago: Hamish Rutherford, Sam Wells, Aaron Redmond (captain), Michael Bracewell, Jesse Ryder, James Neesham, Derek de Boorder, Josh Finnie, Mark Craig, Neil Wagner, Jacob Duffy, Bradley Scott, Craig Smith.
Canterbury (from): Henry Nicholls, Roneel Hira, Neil Broom, Peter Fulton, Brendon Diamanti, Andrew Ellis, Todd Astle, Ryan McCone, Matt Henry, Logan van Beek, Hamish Bennett, Leo Carter.
