If Belgium goes ahead with its plan to host the Davis Cup final against Great Britain on clay, Andy Murray could be forced to miss this year's ATP World Tour Finals in London.
If the Davis Cup Committee gives its approval on Tuesday, the Flanders Expo Arena in Ghent will stage the tie.
The Belgian Federation wants to stage the tie on clay because that is the surface that will give Great Britain's star performer Murray the most trouble.
And Murray has revealed that he might then look to get match practice on clay ahead of the Davis Cup final, rather than take part on the hard courts of the O2 Arena for the World Tour Finals.
"The O2 would obviously be a question mark for me if we were playing on the clay," Murray told BBC Radio 5 live.
"I would go and train and prepare on the clay to get ready for the final.
"You saw last year with Roger Federer that the matches at the O2 are extremely tough and physically demanding.
"If you reach the final and play on the Sunday you also need to take time off – you can't just play five matches against the best players in the world and then not take any days off."