Could Hamish Bond and Mahe Drysdale pair up for Tokyo 2020?
Bond switched to cycling after he and Eric Murray retained their Olympic pair title at Rio 2016.
But last week, he announced his return to rowing despite taking time trial bronze in last year's Gold Coast Commonwealth Games.
And on Monday Drysdale teased the prospect of competing together with a video posted on Instagram.
The Sinkovic brothers, Valent and Martin, are the reigning pair world champions after they won double sculls gold at Rio 2016.
And the Croatian siblings welcomed the challenge.
With Robbie Manson proving himself New Zealand's top single sculler in recent times, Drysdale's hopes of defending his title are in serious doubt.
The invincible pair
Bond and Murray went an incredible 69 races unbeaten since 2009, winning gold at both London 2012 and Rio 2016.
New Zealand pair power to Men's Pairs gold
New Zealand pair power to Men's Pairs goldEric Murray and Hamish Bond, unbeaten since 2009, retain their Olympic rowing title by winning gold for New Zealand in the men's pair final.
They took a break after Brazil with Murray eventually announcing his retirement the following May.
Meanwhile, Bond switched from boats to bikes and showed considerable promise in the individual time trial.
He won both New Zealand national and Oceania titles in 2018 before taking bronze at the Commonwealth Games.
The 33-year-old had hoped to go to last month's Track Cycling World Championships in Poland after beating former world champion Jordan Kerby in the national individual pursuit final.
But his time, a new national record, came after the official cut-off qualifying date with Cycling NZ refusing to put Bond's name forward for a late nomination in the non-Olympic event.
And three weeks later, Bond revealed he was returning to rowing with a view to competing in the eight at Tokyo 2020.
He told Stuff NZ, "I really started to think, 'This could be my last opportunity to get to the Olympics or compete on the big stage.'
"If it is the last thing I do in sport, what do I want to do the most?" - Hamish Bond on his decision to return to rowing from cycling
"What day to day training and environment was I going to enjoy the most? I thought the eight."
Murray swiftly made known that he had no plans to return to competitive rowing, saying, "The mind's probably there but I don't know if the body could do it
"I've spent a couple of years just golfing and drinking beers."
The solo sculler
Like Bond and Murray, Drysdale also took a break from rowing after Rio.
His second gold had come in the most dramatic fashion, edging out Croatia's Damir Martin by five-thousandths of a second.
Drysdale edges out Martin in men's single sculls
Drysdale edges out Martin in men's single scullsDefending Olympic champion Mahe Drysdale wins gold for New Zealand in the men's single sculls in a close finish at Rio 2016.
Before his return to action, Manson broke his world best by three seconds in June 2017 at World Cup II in Poznan, Poland.
Injuries interrupted the 29-year-old's campaign and he finished only fifth in the World Championships in Sarasota, USA.
But Drysdale was unable to displace him from top spot in New Zealand before Manson again took fifth at last year's Worlds in Plovdiv, Bulgaria.
Last Thursday, Rowing New Zealand selected Manson as their single sculler for this year's World Cup and World Championships.
Drysdale had talked of switching allegiance to Fiji for the World Cup ahead of challenging Manson for the sole Olympic berth.
But the 40-year-old said on Instagram last Friday he would not be "running off to Fiji" and that his goal has always been "to represent New Zealand at the Tokyo Olympics and win gold in the single".
The path to Tokyo
Bond and Drysdale would have to prove themselves as a pair on the World Cup circuit ahead of this year's World Championships in Ottensheim, Austria at the end of August.
New Zealand's eight, which finished sixth at Rio 2016, is largely based on the crew which won U-23 world titles in 2013 and 2014.
Two of the eight from Rio, Tom Murray and Michael Brake, were fifth in the pair final at the Worlds in Plovdiv behind the Sinkovic brothers.
If the eight is unable to make a significant impact at world level this year, it is possible Bond and/or Drysdale could join the boat ahead of the Olympic Games.
Drysdale has been training on and off in Canada under former coach Dick Tonks since last October.
Tonks parted company controversially with Rowing New Zealand in December 2015, but was allowed to continue working with Drysdale up to Rio 2016.
He is currently coaching the Canadian national team.