Rafael Nadal says he is continuing to struggle with a back injury as he prepares for the Australian Open to begin on Monday.
Nadal, seeded second behind Novak Djokovic, is trying to win his 21st Grand Slam singles title, which would give him sole ownership of the men's record.
He equalled Roger Federer - who is not taking part in Melbourne after knee surgery - on 20 last October when he won at Roland Garros for his 13th French Open title, but Nadal's ongoing back problem is causing him uncertainty.
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"It's true that for the last 15 days I have been suffering with the back," Nadal said. "So here we are. I tried a little bit today to serve again. I'm doing everything possible to be ready [for the first round]. That's the only thing that I can say.
"The whole positive feelings that I had one week and a half ago, two weeks and a half ago now disappeared a little bit, of course, because I was not able to practice the right way the last week and a half.
"I'm still having not the best feeling possible on the back. But I am practicing again. I did a lot of things to recover. It's not serious, but the muscle is still tight, so it's difficult to play with freedom of movements today.
"Let's hope [the] situation keeps improving. We are doing everything."
Nadal is on the bottom half of the men's draw and is scheduled to play his first-round match against Laslo Djere of Serbia on Tuesday.
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A win there and he could face either Viktor Troicki or Michael Mhom in the second round with a projected third-round match against British No 1 Dan Evans, who recently won his first-ever ATP Tour title at the warm-up Murray River Open.
The Australian Open has been Nadal's least successful Grand Slam venue, with his only title here to date in 2009, although he has come close to adding another on several occasions, losing the final four times at Melbourne Park.
He is now aiming to be the first man in the professional era - and third overall - to win each of the four majors twice, but speaking earlier this week, Nadal insisted the all-time record was not something he was focused on.
"First thing's first, and that's to play the Australian Open, and if that doesn't go well, the season goes on," he added.
"I've never been obsessed with Grand Slams, truth be told."
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