Falvey's late indiscretion last week against Manawatu earned a red card that cost the Irish defender two weeks' suspension.
Falvey's leadership has been a vital part of Otago's central defence and the former professional's influence will be sorely missed.
With five games to play, Otago has the potential to earn 15 more points, and a 22-point total might yet squeeze a place in the top four, but most supporters regard that situation as a long shot.
More realistic is the target of reeling in Canterbury, which is just one point ahead and has a demanding match against Waitakere this weekend.
Returning to the Otago squad after a week's suspension, Andy Coburn is keen to do his bit, and even keener to overtake the Cantabrians is former Dragons player Stu Kelly.
However, much will depend on whether central defenders Mike Smith, Tim Horner and possibly Blair Scoullar can stifle the Waikato attack, which has scored 13 goals this season.
Waikato coach Dave Edmondson still has realistic ambitions of moving up from fifth place since Manawatu and Auckland also have the same points total of 15 in a logjam near the top of the table.
A sideshow in the match could be how effective each team's long-throw exponent is, as Tom Jackson and Waikato's Nathan Strom hurl the ball from sideline to goalmouth seeking to pressure a goal.
The match will be a test for Waikato, which played two games in three days last weekend but has fresh legs in the shape of incoming Stu Hogg, Alex Barlow and Ben Hunt. Edmondson said: "Over the long weekend, two games in three days was always going to be difficult, but three points from the two games was the minimum we had targeted.
It could have been more but for the unfortunate sending off of Joel Mathews in the 30th minute against Waitakere at a time when we were looking dangerous.
"The suspension and a few niggling injuries may give one or two players the opportunity to step up against Otago and I am sure they will jump at the opportunity and allow us to get the result we need.
"With just four games left and the play-off chase so tight, it is vital that we pick up every point available.
"With that in mind we will be targeting an away win against Otago and looking to be more clinical in front of goal to ensure that we convert a greater percentage of the chances that we are creating."
Otago coaches Terry Phelan and Malcolm Fleming want a tighter defence and for the team to capitalise on the goalscoring chances it has been creating.
Otago v Waikato
Sunnyvale, tomorrow, 1pm
Otago United: Liam Little, Rhys Henderson, Tristan Prattley, Barry Gardiner, Mike Smith, Robbie Deeley, Blair Scoullar, Tom Jackson, Dave Dugdale, Andy Coburn, Aaron Burgess, Callum Flaws, Tim Horner, Tom Connor, Stu Kelly.
Waikato United: Jason Mann, Ben Hunt, Graham Pearce (captain), Joe Simpkins, Paul Stewart, Marco Rojas, Stu Hogg, Steven Holloway, Michael Walters, Shaun Van Rooyen, Sam Margetts, Nik Robson, Greg Walters, Alex Barlow, Jon Stables, Michael Mayne, Nathan Strom.
