Andy Murray will not have wanted “to be making up the numbers” as he contemplated his future, says his former Davis Cup team-mate Tim Henman.
The three-time Grand Slam champion and former world number one will retire this year because of a hip injury.
And the 31-year-old Scot says next week’s Australian Open could be the final tournament of his career.
“It is sad news, but it doesn’t detract from what an incredible career he has had,” Henman told BBC Sport.
Former Wimbledon semi-finalist Henman, who has been friends with Murray since the Scot was a teenager, was one of many former players and fans offering their best wishes following the announcement in Melbourne on Friday.
The two-time Olympic champion says he continues to be in “serious pain” as tries to return following surgery on his right hip a year ago.
The operation came after he took six months off court following his 2017 Wimbledon quarter-final defeat by Sam Querrey in a bid to solve the problem.
Murray, who won Wimbledon in 2013 and 2016, says he wants to play at the All England Club this summer before retiring, but admits that might not be possible.
“It has been heading in this direction,” said Henman, who was replaced as British number one by Murray in 2006.
“I know how hard he has been working – I’ve been able to speak to him at different times and I’m close to Jamie Delgado [Murray’s coach].
“With the amount of work he has put in, and we know how professional and diligent he is, 20 months is a long time.
“And with the nature of the injury there were a lot of people who said this was going to happen at some stage.
“He will have ticked every box to give himself the best opportunity to play pain free at the highest level again.
“But the reality is he won’t be able to do that. In professional tennis terms he has seen there isn’t a fix for this hip problem.”
As well as adding the 2013 and 2016 Wimbledon titles to his 2012 US Open triumph, Murray finished runner-up in eight other Grand Slam finals, won the 2016 ATP Tour finals and guided Great Britain to the 2015 Davis Cup.
“When you look at the list of his achievements, there are no greater goals you can achieve in our sport,” Henman added.
“His development, from someone who joined us at the Davis Cup as a 16-year-old, and the way his game has progressed and the way he has matured physically and mentality, has been incredible to watch.
“I know he will be immensely proud of those achievements even though he will be disappointed at the moment.”
Henman, who reached four in the world, also struggled with injury in the final stages of his career – although over a much shorter period than Murray.
“I was very lucky when it came to my retirement and it really happened in the space of six or seven weeks where I was struggling with a number of different aspects,” he said.
“My back wasn’t brilliant at that stage. But also my form, the level of play I was playing at, wasn’t where I wanted, I wasn’t improving.
“And if you’re not improving, your ranking is going to go one way and I always believed I was playing in tournaments to win those tournaments.
“After Wimbledon in 2007 I started on the American hard court swing and felt for the first time I was making up the numbers.
“I felt that wasn’t what my career was about and I think Andy has said similar things.
“He feels he can play to a decent level but when he has been contending for Grand Slam titles and number one rankings he doesn’t want to be there making up the numbers.”