Four-time U.S. Open champion Rafael Nadal won’t defend his title this year, announcing Tuesday that he will skip the Grand Slam event in New York because of concerns about the novel coronavirus.

In doing so, the 34-year-old will forgo an opportunity to tie Roger Federer’s men’s record of 20 major titles.

But the Spaniard, who claimed the 19th major of his career with a five-set victory over Daniil Medvedev at the 2019 U.S. Open, explained that traveling amid the pandemic was at the heart of his concerns in announcing his decision via Twitter postings in Spanish and English.

“The situation is very complicated worldwide, the covid-19 cases are increasing, it looks like we still don’t have control of it,” Nadal wrote.

“This is a decision I never wanted to take but I have decided to follow my heart this time and for the time being I rather not travel."

Nadal, who lives in Mallorca, Spain, is the second elite player to announce he won’t travel to New York for the U.S. Open, which is scheduled to get underway Aug. 31 at the USTA Billie Jean King National Tennis Center without spectators and under strict health and safety protocols.

Nadal’s announcement came just hours after the Madrid Open, a staple of the European clay-court calendar, abandoned plans to hold the already postponed event because of the virus’s spread.

Tennis would seem a relatively safe sport to contest amid a pandemic — certainly more so than contact sports — because of its natural social distancing. But officials are finding that restarting the men’s and women’s professional tours after a four-month hiatus is vastly complicated by the sport’s global nature.

Its four Grand Slams are contested on three continents. And high-profile tuneups and tournaments, such as Washington’s Citi Open and the Madrid Open, are scattered throughout the world. In terms of player safety, it’s the travel that’s proving the major impediment.

Wimbledon officials announced in spring they were canceling the 2020 edition because of the pandemic, which reduced the number of Grand Slams this season to three at a time when Federer, Serena Williams, Novak Djokovic and Nadal are battling age and younger rivals to extend their respective career tallies of major titles.

Federer, who turns 39 on Aug. 8, leads all men with 20 Grand Slam titles. Nadal has 19. And Djokovic, 33, claimed his 17th major at the season’s outset by winning a record eighth Australian Open.

On the women’s side, Williams is without peer in the modern era, with 23 Grand Slam singles titles. She is chasing the one goal to elude her — tying and surpassing Margaret Court’s record of 24 majors — but she turns 39 on Sept. 26.

The French Open, which traditionally precedes Wimbledon, has been postponed to Sept. 27, just two weeks after the U.S. Open. That’s a quick turnaround given the difference in time zones under normal times. Given the heightened health risks posed by air travel, the challenge of contesting both is greater.

In his social-media posts Tuesday, Nadal referred to this season’s reduced tennis calendar as “barbaric,” even as he thanked tournament officials for their efforts to ensure that events could be safely staged.

To limit travel demands on players, U.S. Tennis Association officials relocated the Western & Southern Open, a combined event for men and women, from Ohio to New York to serve as a tuneup, in effect, for the following week’s U.S. Open on its traditional site.

Djokovic, the reigning world No. 1, led the U.S. Open’s men’s entry list unveiled Tuesday, followed by world No. 3 Dominic Thiem and No. 5 Medvedev. Federer, No. 4, previously announced he was withdrawing from all remaining events in 2020 after undergoing a procedure on his right knee. The women’s field is led by world No. 2 Simona Halep of Romania, No. 3 Karolina Pliskova of the Czech Republic and No. 4 Sofia Kenin of the United States. Williams, a six-time U.S. Open champion, announced her commitment to play in June.