Those contacts might include Spain's former monarch, Juan Carlos I, who has lived in the United Arab Emirates since allegations of financial scandals embarrassed the Spanish royal household last year.
According to Spain's El Mundo newspaper, Nadal and Juan Carlos, who is 83, shared a meal on Saturday. The paper also published photos of both of them posing together without masks.
Nadal said he will have to be flexible with his playing schedule because of the positive test.
He played his first match in more than four months on Friday, losing in straight sets to Andy Murray at the exhibition. The 20-time Grand Slam champion's chronic foot injury had forced him to sit out the final months of this season.
Nadal had not competed since early August when he lost to Lloyd Harris in Washington. He missed Wimbledon, the Tokyo Olympics and the U.S. Open.
Also in doubt for the Australian Open is world No 1 Novak Djokovic who remains coy about his vaccination status and, therefore, his participation at Melbourne Park.
While being careful not to name Djokovic specifically, Victorian Premier Dan Andrews suggested earlier this month that Tennis Australia could have the final say on medical exemptions for global tennis stars.
It was a thinly veiled shot at not only Djokovic but the thoroughness of the exemption process. He added that some exemptions were "granted in very questionable circumstances".
His idea came only hours after Australian Open tournament director Craig Tiley distanced the tournament and TA from medical exemptions.
As opposed to Andrews, Tiley tried to add validity to the independent process: "It's very specific as to what is eligible or not, and then that goes through to that expert panel and they'll make a call."
Meanwhile, Dominic Thiem is in doubt for the tournament after announcing he won't contest the ATP Cup or Sydney Tennis Classic – of which he was the headline act for the men.
That news follows the withdrawal of Roger Federer (knee) and Stan Wawrinka (foot) and the mystery around Djokovic's plans.
The women's field also lost reigning Australian Open finalist Jennifer Brady (foot) on Sunday.
Brady joins former world No. 1 Karolina Pliskova (hand) and grand slam champions Serena Williams (hamstring), Bianca Andreescu (personal reasons) and Svetlana Kuznetsova in being out.
