“So if I’m not able to serve at my best and I’m hindered, I’m probably not going to bother playing until I can get it right again.
“I was playing well in the first set, I was obviously up a break serving for the set and … I was obviously struggling a lot.
“I’m serving usually somewhere around the 230 km per hour mark and I wasn’t even able to crack about 180.”
Kyrgios, whose fiery temperament has often landed him in trouble with tennis authorities, said he would consider resting until the Davis Cup finals in Madrid in November.
Australia have been drawn in group D, alongside Belgium and Colombia.
“I want to play [in the] Davis Cup toward the end of the year, that’s mid November,” he said.
“So until … then I’ve got a lot of time, I can rest, recover, get my shoulder right.”
Meanwhile, Gael Monfils fought back from a set down against Cameron Norrie to reach the quarter-finals.
French third seed Monfils came out on top against the Briton to win 5-7, 6-3, 6-4 in an energy-sapping encounter lasting two hours and seven minutes on Wednesday.
Monfils, who had a bye into the second round, will play Albert Ramos-Vinolas in the last eight after the Spaniard’s 7-6 (7-2), 6-3 win against Serbia’s Miomir Kecmanovic.
Eighth seed Ramos-Vinolas saved four set points in the first set as Kecmanovic served while leading 5-4 and 40-0 up.
South Korean qualifier Soonwoo Kwon upset fifth seed Lucas Pouille 7-6 (7-4) 6-2 in their first-round match.