Kyrgios (pronounced KEE-ree-os) posted on Twitter on Friday: "Unfortunately due to a hip issue & tiredness I am not playing in @TennisHalloFame in Newport but thanks for the WC offer guys & good luck!"
The 19-year-old Kyrgios, currently No. 144, became the lowest-ranked man in 22 years to beat the men's No. 1 at a Grand Slam tournament by eliminating Nadal 7-6 (5), 5-7, 7-6 (5), 6-3 in the fourth round Tuesday at the All England Club. Kyrgios then lost in the Wimbledon quarterfinals to No. 8 Milos Raonic on Wednesday.