Asafa Powell's Crystal Palace duel with Justin Gatlin on 28 July could be scrapped unless a deal is reached soon.
Gatlin and Powell share the world record over 100m of 9.77s
"As we speak, there is no agreement," said Powell's manager Stephen Francis.
Powell and Gatlin have yet to race each other over 100m since the American equalled the Jamaican's world record time of 9.77 seconds earlier this year.
But Francis said unless he could reach an agreement with Gatlin's coach Trevor Graham in the next few days he did not think the pair would meet in London.
Powell could also turn his attention to the 200m in Crystal Palace, having recently set the fastest time this year of 19.90 seconds - just four-hundredths of a second off Don Quarrie's 19.86 Jamaican national record.
Wallace Spearmon also ran 19.90s over 200m at the weekend at the United States national championships.
"I am really strong and I can be the best in both events," said Powell, whose next race is on 8 July at the Paris Golden League event.
He added: "I can run anything I want to, I can even go to the 400m.
"I just want to finish the season on top, win all my races and continue to be number one."