Tennis superstar Rafael Nadal is unsure about participating in the remaining events this year, as he is still considering whether to stick to his schedule or return fresh for next year. The Spaniard had a disappointing outing in the ongoing Shanghai Masters losing in the second round to Viktor Troicki.

The 30-year-old, who is currently ranked number five in the men's ATP circuit, is competing with Gael Monfils, Dominic Thiem and Tomas Berdych for a spot in the ATP Finals and will need to participate and take part in more events in order to get the necessary ranking points to book a spot in London.

"It's been tough to be on rhythm and be confident. I cannot say now what I'm going to do during the next month. I'm not 100 percent sure about my calendar, the things I need to do to be ready for the next year. I need to speak to my team. I need to speak to my uncle too", Nadal said, as quoted by tennis.com.

The Spaniard has struggled in the past couple of years with a succession of injuries and poor form taking a toll. Persistent back and knee problems have ensured that his participation in tennis events around the world is limited and it is these recurrent injuries that have contributed to his poor form of late.

Nadal last Grand Slam victory was the 2014 French Open title. The Spaniard is also mulling taking some time off from the game and using that time to get additional practice for the challenges that lie ahead.

"It's a tough part of the season for me. The tournaments are difficult. Surfaces are difficult. Sometimes continuing to compete is not the solution. Sometimes the solution is practice, and stop and continue the process of training. And maybe it's an opportunity to do that. I'm not sure", the former world number one added.

Nadal is next scheduled to participate in the Basel ATP event that starts in two weeks.