Canadian star Felix Auger-Aliassime was one of several notable absentees when the players' list for the upcoming Singapore Tennis Open was released on its official website yesterday.
The world No. 19, who reached the fourth round of the Australian Open before losing to surprise semi-finalist Aslan Karatsev of Russia, had been scheduled to feature in the week-long tournament, which starts tomorrow at the OCBC Arena.
Others who will no longer be making the trip for the ATP 250 event include British No. 1 Daniel Evans (world No. 26) and Norwegian Casper Ruud (No. 28).
Instead of Auger-Aliassime, French world No. 36 Adrian Mannarino is now the top seed. Other high-profile names include 2014 US Open champion Marin Cilic, Australian John Millman and Japan's No. 2 player Yoshihito Nishioka.
The top four seeds of the 28-player singles field - Mannarino, Millman, Cilic and Alexander Bublik - will receive a bye in the first round.
Lim Teck Yin, tournament organising chairman and Sport Singapore chief executive, said in a virtual media conference on Friday that the list has moved "quite dynamically" from the planned one.
Players had "multiple considerations" in deciding if they were coming, he said, and some have pulled out because of injury or personal reasons.
The US$300,000 (S$397,740) Singapore Open was a late addition to the men's circuit and follows the Australian Open in Melbourne, where some players will be coming from. The year's first Grand Slam ends today.
At least 200 people, including players, staff and officials, are expected from overseas for the Singapore Open and will have to take daily polymerase chain reaction (PCR) tests throughout their stay.
Locals Shaheed Alam and Roy Hobbs lost in yesterday's first qualifying round.
Shaheed fell 6-1, 6-3 to Tunisia's Malek Jaziri while Hobbs succumbed 6-1, 6-1 to Australia's John-Patrick Smith.
Both Singaporeans had received wildcards to compete in the qualifying rounds and will be in action in the main doubles event.
The tournament will be behind closed doors, but up to 250 fans may be allowed for the semi-finals and final if there are no tournament-related positive coronavirus cases, among other factors like local transmissions, organisers said on Friday.
More information can be found at hub.tennis.