"The guy can flat out play on grass" - Roddick thinks Kyrgios will be a real threat at Wimbledon

Retired American tennis star Andy Roddick acknowledged there is a lot of unpredictability when it comes to Nick Kyrgios but added one thing is for sure - the Australian can play extremely well on grass.

Grass is a surface that perfectly suits Kyrgios' aggressive game-style and many think the Aussie is the player to watch out at Wimbledon this year, with Roddick being one of them.

"Yeah, the thing about Kyrgios is can his body hold up? Do we know if he has been training? One of the things that makes him so fantastic to watch is we just don't know where his body is at," said the former World No.1 on the Tennis Channel.

"We don't know where his game is at most of the time. But one thing we do know is the guy can flat out play on grass, he is not scared to go against the biggest names of the game, Centre Court, big courts, he likes those even more.

"So, you don't want to have him if you are a seeded player anywhere near your name in the first couple of rounds."

Kyrgios made his Wimbledon debut in 2014, losing to Milos Raonic in the quarterfinals. Although the 27-year old has not had any strong performances in recent years, he did reach the third round at last year's event.