Only one thing has stopped Rafael Nadal from breaking every existing record and probably becoming the greatest player to ever play the game of tennis - injuries.

Debilitating injuries - particularly to his knees - have halted the Spanish matador's charge to undisputed greatness. Nadal is still considered one of the greatest to ever play the game, with good friend Roger Federer, rightly, regarded as the best ever. But many would wonder what could have been, had the Spaniard not missed so many tournaments due to injury.

After a shock second round loss at Wimbledon, Nadal has not played a single game -- another knee injury keeping him out of the U.S. Open and painfully, the London Olympics, where he would have tried to defend his gold medal and also carried the Spanish national flag at the opening ceremony.

"For me (missing) the Olympics was very tough," the 26-year-old told the Daily Mail. "I was very, very sad for three weeks around then. I had the chance to carry the Spanish flag. It only comes every four years. Missing the U.S. Open was hard, but you think you will have more chances.

"The Olympics is once every four years and you don't know how many more you will get. I will work very hard to be in Rio but it is in four years. I am 26-and-a-half, I love competition, playing tennis, and this was actually a season I enjoyed playing more than others.

"I have the motivation to come back and that's what I'm going to try."

Hindsight is a wonderful thing, and looking back Nadal admitted that playing in Wimbledon, while carrying an injury, might have not been the smartest thing he has done. "Was it a mistake to play at Wimbledon? Maybe, but when you are playing well it is hard to stop," he said. "At Roland Garros I had to play with anti-inflammatories to get through.

"After that I felt really bad. My practice before Wimbledon was terrible. I played the first round with injections, otherwise it would have been impossible. That doesn't help the knee.

"I've played a lot in pain before as other people have done. The problem is when you run and you are thinking about where you are planting your leg. It is impossible to compete like that."

One of the most liked players in the circuit, Nadal hopes to make a return at the Australian Open, with the Spaniard pretty much ruling out competing in the ATP World Tour Finals in November. "All that is in my mind is to keep working hard to come back," Nadal said.

"I cannot think about the future because it's not like if you break your arm and you know you will have a few weeks like this, then a few weeks like that and then you are back. This is a day-by-day thing, I have checks every week to see how I'm improving. I can't predict what will happen.

"I hope you see me in Australia. That is the biggest goal for me, to come back just before then in Qatar, but I cannot say for sure it is going to happen.

"The only thing is to recover well. I want to be 100 percent when I come back. I don't want to keep playing every day with doubts, not knowing if my knee is going to answer all the questions."