Masters champions Hideki Matsuyama and Bubba Watson have become the latest players to withdraw from The 149th Open.
Matsuyama's preparation for the final major of the year was disrupted after he tested positive for Covid-19 during the Rocket Mortgage Classic last week, and he continued to test positive during his self-isolation.
The Japanese star insists he feels fit and healthy and has no coronavirus symptoms, but he has ruled out making the trip to Royal St George's along with Watson, who has been a "close contact of an individual testing positive for Covid-19".
"I'm feeling fine but haven't been able to practice in preparation for The Open," said Matsuyama via a statement issued by the R&A.
"Combining that with the difficult travel to the UK, my team and I have decided it's best to withdraw to ensure everyone's safety. I feel badly missing The Open and look forward to playing again at St Andrews next year.
"I'd like to thank the many golf fans for their continued concern and support as I strive to return to the game I love as soon as possible."
Five players have now withdrawn from The Open this weekend, with Matthew Wolff, KH Lee and Danny Lee pulling out on Saturday while Kevin Na withdrew last week due to the various travel restrictions. Former Players champion Si Woo Kim and fellow South Korean Sungjae Im have also opted out to focus on the Olympic Games next month.
Many players have voiced their disapproval of the strict protocols in place for the Championship, which require all competitors to adhere to the tournament "bubble", staying in authorised accommodation and being limited to a support group of four people under the same roof.
Players will not be permitted to visit local shops, bars or restaurants in accordance with the government health and safety guidelines put in place for the week.
Matsuyama was replaced by Harold Varner III and Watson's place now goes to Brendan Steele, and 2001 champion David Duval also withdrew on Sunday evening, ensuring an Open debut for John Catlin, and leaving Adam Long, Sam Horsfield and Dylan Frittelli as the next three players on the list of reserves.