With preparations underway for the U.S. Open tennis at Flushing Meadow, the loss of Stan Wawrinka and Rafael Nadal would cast an immediate shadow over a tournament that has courted controversy from the moment it was announced.

With the rumoured withdrawal of Rafael Nadal, the certain lack of a recooperating Roger Federer and now the news that Stan Wawrinka has been training on clay courts, the U.S. Open at the end of August looks set to be without some of its brightest stars.

Players who are playing in the Grand Slam event should, by now, be training on hard courts, perfecting those booming forehands and nailing down that first-serve percentage. Maybe nailing it up might be a better term, but you know what we mean. They need to be sharp, focused and ready for the action at Flushing Meadow.

The reveal that came as part of a typically honest Stan Wawrinka Instagram story that the Swiss superstar has been practicing with Roland Garros 2020 tennis balls on a clay court all but confirms that he’ll be missing from the line-up in the United States too.