New Delhi, April 14 : Rafael Nadal, who has been struggling with an ongoing hip injury, on Friday announced that he will not compete at the upcoming Barcelona Open, saying he is still in the preparation process for his return. The 22-time Grand Slam winner remains doubtful for the French Open in May, where he is defending champion, as he has been out of action since his Australian Open second-round loss to American Mackenzie McDonald, where he aggravated a hip injury. The 36-year-old Spaniard had also withdrawn from the Indian Wells Masters and Miami Open as well as the ongoing Monte Carlo Masters due to grade 2 injury in the iliopsoas muscle in his left leg. "Barcelona is a special tournament for me because it's my adopted club and because playing at home is always a unique feeling," Nadal tweeted. "I'm still not prepared and therefore I'm still in my preparation process for the return to competition," he added. The Barcelona Open, where Nadal is a 12-time champion, starts on Monday and is one of the last big clay-court events before the French Open begins in Paris on May 28. Earlier, the Spaniard had fallen out of the top 10 in the ATP rankings for the first time since 2005 after missing nearly three months on tour. This year he has played four matches -- two at the United Cup and as many as at the Australian Open and lost three of them. His only win came against Britain's Jack Draper in the first round at Melbourne Park. /IANS