World number four Kei Nishikori has pulled out of the Western and Southern Open with an injury.
"I kind of got hurt last week in Montreal in the last match against Andy (Murray). I (have) played a lot of matches from Washington and played four matches in Montreal so I was a little bit tired in my body but my hip was a little bit bothering me so I couldn't really finish the match."
The 25-year-old says he still plans to take part in the US Open at the end of the month.
