The Rovers and Wairarapa belong to the Central region so Wairarapa, pending NZ Football appeal committee's decision in the next few days, are scheduled to play away against Palmerston North Marist while Wellington Olympic host Lower Hutt City in the capital city derby from the Central soccer catchment area.
The other two regions are Northern, which will stage four games, and Southern which has two games.
The player in question is Brian Kaltack, who came off the bench in the dying minutes as a defender.
A Vanuatu international, Kaltack plays in the Solomon Islands for Solomon Warriors FC on loan from Erakor Golden Star and participated in the O-League in the 2012-13 season in a competition that includes Auckland City and Waitakere United.
The 19-year-old made his international debut in 2011 and also that year played for Waterside Karori.
According to Wikipedia website, Kaltack trained with A-League campaigners Wellington Phoenix from July 2011 until late January 2012 at the invitation of former coach Ricki Herbert. He also received $15,000 support from Oceania Football Confederation to cover costs.
It is understood Wairarapa coach Phil Keinzley spotted the player during the Under-23 Olympic qualifiers held in Taupo last year.
Rovers chairman Russell Booth last night said NZ Football cleared Kaltack to ply his trade for Wairarapa as a "reclassified player", which paved the way for a "guest player" to represent a club as a "local".
"Wikipedia lists him as having four starts and picking up two cautions in two games," Booth said, who also questioned how Kaltack could be a guest player when NZF had reclassified him a local.
"How can he be that if he played in the O-League?"
The premiership rules state that if a player leaves New Zealand to play for another country or its club then on returning here their eligibility for a non-stop 12 months as a "non-guest player" starts all over again.
Keinzley last night issued a brief statement to the Wairarapa Times Age: "[We're] absolutely confident that no rules were broken - all players were registered."
Booth said the clearance of players was a "grey area" and it was also in the Rovers' interest to know where they stood with their overseas players - English import Aaron Jones and Ezequiel Dondiz, of Argentina.
In line with the ASB Premiership national league in summer, the rules allow teams to have three guest players only.
Keinzley has over the years had a rash of overseas talent, especially from the Pacific Islands, in a squad that has a United Nations look about it.
His three latest players from overseas include Frenchmen striker Charles-Francois Mallman and midfielder Alsseny Cissoko as well as Spain-born, England-based George Jermy.
"The three know each other and I understand they have played in the same club in England."
The other overseas player is Fijian Esava Naqeleca but it is not clear what his status is with the three guest players' positions taken in the squad.
Booth said if Keinzley was confident that was great but Rovers also wanted to know for their benefit.
"That's why you have paid administrators [Central Football]. You can take players at face value but we do all our checks," he said, adding they had got Central Football Eastern manager Phil Holt to go through the appeal before submitting it to NZ Football.
In the first round of cup action this year, NZ Football disqualified FC Twenty11 and Universities in a Christchurch derby for fielding unregistered players, thus enabling Waimakariri United to go to round two on a bye.
In 2008, North Shore United suffered a similar fate to a Sunday side, New Zealand Celtic Supporters.
The Rovers v Wairarapa game is unlikely to be a rematch amid speculation because any team breaching registration rules is disqualified.
Another issue is whether having a player on the card is a breach, regardless if they play.
