Andy Murray was forced to withdraw from his Queen’s Club Championship match against Jordan Thompson on Wednesday with a back injury.
Murray, 37, looked uncomfortable walking to the court before the match started. He then required treatment on his lower back from his trainer just a few minutes into the round-of-16 match.
Despite attempting to play on, Murray was forced to retire with Thompson leading 4-1.
The former world No.1 has been named to represent Great Britain at the Olympics in Paris this summer, while Wimbledon starts on July 1.
Murray has said it would be “fitting” to finish his career at the Olympics or his home Grand Slam.
Earlier in men’s doubles, British duo Jack Draper and Cameron Norrie were knocked out in the round of 16 in two sets.
The pair went down 6-4, 6-4 to Edouard Roger-Vasselin and Santiago Gonzalez.
At the Birmingham Classic, Heather Watson and teammate Greet Minnen advanced to the quarterfinals of the women’s doubles competition with a 6-3, 6-2 win over Erin Routliffe and Gabriela Dabrowski.
Watson and Minnen will face Miyu Kato and Zhang Shuai in the quarterfinal on Thursday.