Mok Ying Ren and Soh Rui Yong, Singapore's two top marathoners, have been pencilled in to compete at the World Half Marathon Championships at the end of the month.
But the March 26 showdown in Cardiff between the duo - two of the Republic's finest long-distance athletes - may not materialise after all.
Mok, 27, admitted that it would be difficult for him to compete at the World Championships due to the late invitation he received yesterday. As he intends to run a full marathon this weekend, he cited the short recovery time as a factor in determining whether he would participate in the event or not.
The 2013 SEA Games champion and current national record holder in the event (1hr 7min 8sec) said: "I had a good experience at the last championships I ran in Copenhagen in 2014.
"But I've just received the (invitation) today. It's a bit late as the competition is just a few weeks away. The timing of the event is a bit off for my schedule.
"I need to discuss with my coach, because I might not be able to recover in time (for the event), and I don't want to take any risks."
Mok and Soh, who have developed a fierce rivalry in long-distance running, last raced each other in the San Jose Rock 'N' Roll Half Marathon in California last September. Mok ran 1hr 8min 22sec while Soh clocked a time of 1:07:21.
This time, both have been selected by the Singapore Athletic Association (SAA) to help them in their preparations to qualify for the Rio Olympic Games in August.
With the qualifying window for the Olympics closing on July 11, Soh is scheduled to run the April 24 London Marathon in his bid to qualify for the Olympics. The qualifying mark is 2hr 19min.
Said SAA general manager Damon Yong: "We have looked at their training programmes and plans, and also their performances. Both of them have stated their intention to qualify for the Olympics. Since we are able to support them, we selected both of them to go (to Cardiff).
"At the event, they would be able to race with the world's best and it would help them to ramp up their preparation for the full marathons."
Soh agreed. Said the 24-year-old 2015 SEA Games champion, who is spending seven weeks training in the high-altitude town of Iten in Kenya: "The main thing is to qualify for Rio. But this will be a good warm-up for a marathon and I can shake off some rust.
"I can do some speed work over there, because in a (full) marathon, it's always a long run. But in a half marathon, it's a long and fast run."