Andy Murray expressed concern for Novak Djokovic on Sunday, saying that other players were shocked and the circumstances surrounding the world number one's barred entry into Australia was "really not good for tennis".
The Serb was hoping to win a record 21st Grand Slam at the Australian Open later this month, but instead of training he has been confined to a room in a hotel in Melbourne used to accommodate asylum seekers.
Djokovic, 34, is challenging the decision to cancel his visa after being stopped on arrival at Melbourne Airport early on Thursday, and a hearing into the case will be held on Monday.
"I think everyone is shocked by it, to be honest," former world number one Murray was quoted as saying by local media in Australia."
World number one Novak Djokovic "failed to provide appropriate evidence to meet the entry requirements to Australia" and his visa has been cancelled, the Australian Border Force has announced.
Tess Derry
The two have faced off a number of times, most famously at Wimbledon in 2013 where Murray beat Djokovic to become the first Brit to win the tournament since Fred Perry in 1936.
"I hope that Novak is OK. I know him well, and I've always had a good relationship with him and I hope that he's OK."
Great Britain's Andy Murray and Serbia's Novak Djokovic with their trophies on day thirteen of the Wimbledon Championships at The All England Lawn Tennis and Croquet Club, Wimbledon.
Adam Davy
"It's really not good for tennis at all, and I don't think it's good for anyone involved."
Djokovic, who has publicly criticised mandatory vaccines, has consistently refused to disclose his inoculation status and said he had been granted a medical exemption to compete in Australia.
Australian Open chief Craig Tiley blamed conflicting and quickly changing directives in a "challenging environment" for the confusion that resulted in Djokovic being refused entry to the country on a medical exemption.
"(I need to) wait and hear exactly what the situation is before commenting on it further, because again I don't think it's fair because some of it is speculation," Murray said.