Rafael Nadal has pulled out of the BNP Paribas Open a day before he was supposed to play his first official match in two months.

Pro tennis players have been wondering aloud whether arm injuries in their sport are related to the week-to-week changing of the tennis balls used by tournaments.

The 2023 U.S. Open features several players who have made comebacks to tennis after being away for a while.

Reaction to Roger Federer’s announcement that he will retire from tennis after the Laver Cup in London next week.

Novak Djokovic is 26-0 in Grand Slam matches in 2021.

Fifth-ranked Sofia Kenin has pulled out of the U.S. Open because she recently tested positive for COVID-19.

How well do you know the U.S. Open tennis tournament.

Ashleigh Barty of Australia, returns to Victoria Azarenka of Belarus, during the Miami Open tennis tournament, Monday, March 29, 2021, in Miami Gardens, Fla. (AP Photo/Marta Lavandier)MIAMI – Ash Barty is tough to beat under any circumstances, especially when she’s on the ropes. The world’s top-ranked player has reached the Miami Open quarterfinals, getting there by holding off 14th-seeded Victoria Azarenka of Belarus 6-1, 1-6, 6-2. This, too, was cool: The match lived up to its showdown potential, with the reigning Miami Open champion and current world No. 1 in Barty facing someone who has won the Miami title three times and a previous world No. Svitolina will play unseeded Anastasija Sevastova of Latvia in the quarters; Sevastova was a 6-1, 7-5 winner over wild-card Ana Konjuh of Croatia.

Serbia's Novak Djokovic hits a backhand return to Canada's Milos Raonic during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Feb. 14, 2021. For anyone curious about the severity of his injury, he put it into context after qualifying for the Australian Open quarterfinals for the 12th time. The eight-time Australian Open champion planned to spend most of the next two days recovering ahead of his quarterfinal against sixth-seeded Alexander Zverev. “If you’re here, it’s for a reason - there’s no doubt about it,” Dimitrov said after his 6-4, 6-4, 6-0 win. AdAnd not since Patrick McEnroe — John’s brother — in 1991 has a man ranked as low as 114th made it to the Australian Open quarterfinals.

AdHe said: “If it’s any other tournament than a Grand Slam, then I’d withdraw from that event, that’s for sure. Defending champion Novak Djokovic has started his fourth-round match against Milos Raonic at the Australian Open. He'll play either U.S. Open champion Dominic Thiem or Grigor Dimitrov next and he says he doesn't have a preference. Their match is to be followed by eight-time Australian Open champion Djokovic against 2016 Wimbledon finalist Milos Raonic — assuming Djokovic decides he can play. Other men in action include reigning U.S. Open champion Dominic Thiem and the man he beat in that final, Alexander Zverev.

Serbia's Novak Djokovic celebrates after defeating United States' Talyor Fritz in their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Feb. 13, 2021. So I don’t know if I’ll manage to recover from that in less than two days. “Let’s see what happens tomorrow.”The only man in the draw with more Grand Slam trophies than Djokovic, No. Let’s be honest.”This setback dropped Fritz's career record in third-round matches at Grand Slam tournaments to 0-6. I just want to make it to the fourth round," Fritz said.

Serbia's Novak Djokovic makes a forehand return to United States' Frances Tiafoe during their second round match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Feb. 10, 2021. 1, had never beaten anyone in the Top 5, and now he'd just won a tiebreaker against Novak Djokovic to level their second-round match at the Australian Open. But it wasn't quite enough to beat the eight-time Australian Open champion, who won the 3 1/2-hour afternoon match 6-3, 6-7 (3), 7-6 (2), 6-3. AdAnother U.S. Open champion, Naomi Osaka, needed only an hour to sweep Caroline Garcia 6-2, 6-3. 29 Ugo Humbert 5-7, 6-4, 3-6, 7-6 (2), 6-4 in a rollicking night cap full of turns and twists.

United States' Serena Williams makes a forehand return to compatriot Danielle Collins during a tuneup event ahead of the Australian Open tennis championships in Melbourne, Australia, Friday, Feb. 5, 2021. 3 Naomi Osaka, the U.S. Open champion. Two-time Australian Open champion Victoria Azarenka, Johanna Konta and Elina Svitolina are also in Kenin's quarter. Williams already has won seven Australian Open titles and her 23 major titles is a record in the Open era. In the top half, Djokovic’s bid for a third consecutive Australian title — and ninth overall — could get tricky.

An Australian Open courtesy car waits outside the Grand Hyatt hotel in central Melbourne, Australia, Thursday, Feb. 4, 2021. All competition at six Australian Open tuneup events scheduled for Thursday was called off after a worker at one of the tournaments' Melbourne quarantine hotels tested positive for COVID-19. The Australian Open is scheduled to begin Monday. Williams won her last major title at the 2017 Australian Open, when she was pregnant with her daughter, Olympia. On the bottom half of the draw, defending Australian Open champion Sofia Kenin rallied from a set and a break down to fend off Jessica Pegula 5-7, 7-5, 6-2.

Germany's Alexander Zverev reacts after winning his semi-final game against Spain's Rafael Nadal at the Paris Masters tennis tournament in Paris, Saturday, Nov. 7, 2020. (AP Photo/Thibault Camus)PARIS – Alexander Zverev advanced to the Paris Masters final for the first time by beating top-seeded Rafael Nadal 6-4, 7-5 on Saturday, denying Nadal the chance to win a tournament that continues to elude him. Zverev goes for his fourth Masters title and 14th overall, while 2019 U.S. Open runner-up Medvedev is seeking his third Masters crown, eighth career title and first of this year. Zverev won 78% of points on first serve compared to 60% for Nadal and led 9-1 in aces in that set. Earlier, Medvedev reached the Paris Masters final for the first time after beating Milos Raonic 6-4, 7-6 (4) in a contest between big servers.

1-ranked Novak Djokovic and former top-30 member Vasek Pospisil would be the co-presidents of a new group they are trying to set up to represent mens professional tennis players. A letter emailed to players -- and obtained by The Associated Press on Friday -- pushes the formation of a Professional Tennis Players Association, abbreviated PTPA. Unlike many other professional sports, mens professional tennis has never had a representative body that is represented for players by players, the email said. The mens tennis tour is organized by the ATP; the womens tennis tour is run by the WTA. Djokovic is the president of the ATP Player Council and Pospisil has been a member for two years, but he tweeted Friday night that he was resigning.

Novak Djokovic, of Serbia, front, holds his winning trophy after winning his match with Milos Raonic, of Canada, at the Western & Southern Open tennis tournament Saturday, Aug. 29, 2020, in New York. Has been challenging mentally and emotionally for me to stay sane and be able to compete on the highest level and win this title, Djokovic said. I just hope Im giving myself, you know, the opportunity and the chance to have enough time to recover ahead of the U.S. Open, Osaka said. Djokovic also won the Western & Southern Open in 2018 and is now the first man to win each Masters 1000 event one level below the Grand Slams at least twice. Osaka initially felt a problem with her leg in her first match of the Western & Southern Open and said she pulled the hamstring in the second-set tiebreaker of her semifinal Friday.

Naomi Osaka, of Japan, leaves the court after winning her match with Anett Kontaveit, of Estonia, during the quarterfinals at the Western & Southern Open tennis tournament Wednesday, Aug. 26, 2020, in New York. Soon after, the whole tournament was put on hold for a day. Osaka tweeted that as a Black woman, she feels compelled to pull out of the tournament to put a focus on police shooting Black people. "Watching the continued genocide of Black people at the hand of the police is honestly making me sick to my stomach. I have to be patient, to try to enjoy every single match I play here after six months without competing.

Novak Djokovic, of Serbia, returns a shot from Tennys Sandgren during the third round at the Western & Southern Open tennis tournament Tuesday, Aug. 25, 2020, in New York. (AP Photo/Frank Franklin II)NEW YORK Novak Djokovics neck felt much better, and his tennis looked much better, in a 6-2, 6-4 victory over unseeded American Tennys Sandgren at the Western & Southern Open on Tuesday that improved the No. The Western & Southern Open is usually held in Ohio but was moved to the U.S. Opens site in Flushing Meadows this year to make for a two-event, no-spectator bubble amid the pandemic. He has won five of the past seven Grand Slam tournaments, including at the Australian Open in February. Womens quarterfinal matchups set earlier in the day were two-time Grand Slam champion Naomi Osaka against Anett Kontaveit, former No.