The Spaniard pulled out of the contest after suffering an abdominal tear during his marathon quarter-final win over Taylor Fritz.
It means that Kyrgios will now appear in his maiden major final on Sunday, which few people would have been expecting at the start of the tournament.
The 36-year-old took part in a practice session away from the cameras on Thursday, but he was thought to have had issues with his serve.
The Australian star will be eagerly waiting to see who he faces in the showpiece event, with Novak Djokovic and Cameron Norrie meeting today in their semi-final.
Speaking at an emotional press conference, Nadal revealed his withdrawal was the only decision he could make.
He said: “The most important thing is happiness more than any title.
“I can’t risk that much and stay two, three months outside of the competition because that’s going to be a tough thing for me.
“If that happens, it happens, not because I was not doing things the proper way.
“Very tough circumstances in that one I think it’s obvious if I keep going the injury is gonna get worse and worse. I made this decision because I can’t be competitive and win the next two matches.
“I don’t want to make things worse, but I am very sad.”
Despite all the recent controversies, Kyrgios showed his support for the 22-time Grand Slam champion.
He posted: “Different players, different personalities. Rafael Nadal, I hope your recovery goes well and we all hope to see you healthy soon. Till next time….”
The 27-year-old saw off Chilean player Cristian Garin in the quarter-finals and he becomes the first player in the Open era to receive a walkover into a Wimbledon final.
It means that he will have a four-day break between his quarter-final and the final so he should be well rested for the biggest occasion of his career.
Kazakhstan’s Elena Rybakina and Ons Jabeur of Tunisia will meet in the ladies final on Saturday.