Three-time Grand Slam champion Murray, 37, was forced to retire from his second-round match against Jordan Thompson at Queen’s on Wednesday.
He was trailing Australia’s Thompson 4-1 in the first set when he decided he could not continue.
The two-time Olympic gold medallist is set to retire later this year and this week said ending his career at either Wimbledon – which starts on 1 July – or Paris 2024 would be “fitting”.
The former world number one remained hopeful on Wednesday that the back issue which ended his Queen’s farewell would not deny him a final appearance at Wimbledon, where he is a two-time champion.
Speaking on BBC Two on Friday, Jamie Murray said of his brother’s situation: “He saw a specialist yesterday evening and he’s basically trying to decide what his next move is.
“I don’t think it’s right for me to go into that personally, that’s up to him, but I think he has got a few decisions to make.
“It’s obviously incredibly disappointing for him that this was potentially going to be his last Queen’s, last Wimbledon and Olympics, and there’s a potential that that might not be able to happen.
“I think he’s got to make a few decisions, and see where he goes from there.”
Murray, who underwent a hip resurfacing operation in 2019, ruptured ankle ligaments at the Miami Open in March before his ongoing back problem was exacerbated by playing on clay.
He won his first-round match at Queen’s against Australia’s Alexei Popyrin – the world number 48 – in three sets on Tuesday, but struggled from the start as he attempted to play through discomfort against Thompson a day later.
Murray is now in a race against time to be fit for Wimbledon, with the tennis at the Olympics also beginning next month, on 27 July.
Fellow Briton Dan Evans has had a scan after he had to retire with a knee injury following a fall during his Queen’s opener against American Brandon Nakashima.
