The 20-time Grand Slam champion tested positive for Covid-19 after returning home from an exhibition tournament in Abu Dhabi, saying he had experienced "some unpleasant moments".
A number of other players who were in Abu Dhabi also tested positive, including Russia's world No 5 Andrey Rublev, women's Olympic champion Belinda Bencic and US Open champion Emma Raducanu.
Nadal's arrival will be a boost for the organisers of the first Grand Slam tournament of the season, which starts on January 17.
There are still major doubts over whether world No 1 Novak Djokovic will play.
The 34-year-old withdrew from the ATP Cup team event days before its start on Saturday, heightening doubts over whether he will defend his Australian Open title.
Djokovic, a nine-time champion in Melbourne, has refused to confirm if he has been vaccinated against Covid-19, with all participants needing to be jabbed or have a medical exemption.
The field in Australia has been ravaged by injuries, with superstars Serena Williams and Roger Federer out, along with Dominic Thiem, Jennifer Brady, Karolina Pliskova, Bianca Andreescu and Karolina Muchova. (AFP)
Aribo ready to fight for EPL survival
Adesanya vows to make UFC return after third straight loss
We Apologize To Our Father Dr Peter Odili On Behalf Of His Children Who Have Gone Astray – Edison Ehie
Aston Villa closing in on Rashford loan deal
Adesanya aims for comeback as UFC lands in Saudi
Alonso delighted with Boniface stay
EPL: Wood’s hat-trick fires Nottingham Forest to 7-0 thrashing of Brighton
PDP Governors Announce Date For Party’s NEC Meeting
PDP governors back Appeal Court verdict, endorse Ude Okoye as national secretary
Everton plot £33m Awoniyi move
Barcelona’s Pedri extends contract to 2030
Boniface rejoins Leverkusen training after failed Saudi transfer
Rangers International going, going . . . (55,270 views)
Amaju Pinnick: A cat with nine lives (46,426 views)
Second Term: Amaju Pinnick, Other NFF Heavyweights Home to Roost •How Pinnick Broke the Jinx (44,458 views)
Missing $150,000 IAAF Grant: Solomon Dalung’s Hide and Seek game (44,101 views)
Sports Development: Zenith Bank on the zenith (44,052 views)
Current issues in Nigerian sports: Matters arising (44,040 views)
Gov. Abdullahi Ganduje’s solid footprints, commitment to sports development in Kano State (43,849 views)
NFF Presidency: Pinnick, Maigari, Ogunjobi, Okoye in Battle for Supremacy (43,413 views)
Olopade, BET9A wave of revolution in NNL (42,501 views)
Commonwealth Games 2018: Shame of Muhammadu Buhari, Solomon Dalung (41,150 views)
Ibrahimovic’s Man U exit: Whose decision is it? And in whose interest? (39,591 views)
John Mikel Obi: Segun Odegbami’s Outrageous Call! (39,022 views)