CINCINNATI: Three-time Grand Slam winner Andy Murray said Sunday the absence of the "Big Three" players at this week's ATP Cincinnati Masters will have a chilling effect on the US Open tuneup event.

The field, headed by Russian Daniil Medvedev, is without resting world number one Novak Djokovic plus injured Rafael Nadal and Roger Federer.

Murray, a two-time Cincinnati champion playing on a wild card, said the atmosphere is somewhat odd.

"It's a different landscape, for almost all of my career those guys have been there," Murray said.

"But things are changing. Bodies are breaking down instead of (top) players being overtaken by tennis (progress).

"It gives a big opportunity for other players to win the title when those guys are not playing."

The 34-year-old Scotsman, who has dealt for several seasons with a pair of major hip procedures and the resulting difficulties in making a full comeback, wished all three absent stars well in their own healing ahead of the August 30 start of the US Open.

"I hope all of them get physically fit and ready for the US Open. But that is looking unlikely unfortunately for Roger and Rafa.

"It would be a shame if they missed the Open this year."

Murray said his own planning has become a short-term exercise due to ups and down in his fitness level.

After firing up for the summer grass and reaching the Wimbledon third round, Murray and partner Joe Salisbury won two matches at the Tokyo Olympics before losing their third.

But post-Games, he was diagnosed with a tear in a quad muscle, which set back training progress again and which will get its first test in the opening round against a qualifier.