Swiss legend Roger Federer has hinted he isn't ready to retire just yet following his most recent social media post.
The 20-time Grand Slam champion hasn't played on the ATP Tour since last summer's Wimbledon due to a knee injury.
Federer's last match saw him eliminated in the quarter-finals of the grass-court event to Hubert Hurcakz, and the former world number one admitted he may miss this season's SW19 event.
However, the 40-year-old posted an update on Monday night of him working out in the gym and added the caption: "Rehab is rockinggggggg."
Federer is regarded as one of the greatest players of all-time but no longer holds the record for most Grand Slam wins.
Rafael Nadal overtook him and Novak Djokovic (both on 20) after winning this year's Australian Open to earn his 21st title.
When it comes to the 'GOAT' discussion though coach Carlos Rodriguez admits he 'can't choose' between Federer or Nadal.
"I cannot choose Roger Federer without mentioning Rafael Nadal," he told The Functional Tennis podcast.
"I don't agree with those people who necessarily want to choose just one. Roger and Rafa have improved each other and shared the biggest stages for a decade and a half. Then came Novak Djokovic, who is very different from the two of them.
"Federer and Nadal are two true gentlemen, I can't choose one or the other. I opt for both."
Former tennis star Alexander Waske is hopeful Federer can recover from injury and have a fairy-tale ending to his career.
"Let's hope his career doesn't end due to injury.
It would be a very bad thing both for him and for all fans of this sport. Roger deserves a worthy ending."