Kevin Na has withdrawn from the British Open next week at Royal St. George’s because of the international travel requirements getting to England.

He was replaced in the field by two-time major champion Martin Kaymer.

“It was a tough decision, but for my family and me it is best to skip the Open this year,” Na said in a statement released by the R&A. “I will be back next year. It is one of my favorite weeks and I would love to hold the claret jug one day.”

Na qualified by being among the top 50 in the world ranking (No. 37) after the PGA Championship. He won the Sony Open at the start of the year.

Na is eighth player, not including past champions, to withdraw and the second American. Charles Howell III also chose not to go, though he has missed before. Three players, including Sungjae Im and Siwoo Kim, cited their preparations for the Olympics.

Na did not specify the travel requirements in the R&A statement. Among the strict guidelines is limiting who can travel with the player. Each player can have a caddie and two additional members of his core group such as a coach, trainer, translator or family member.

The family member, such as spouse, would not be exempt from U.K. quarantine requirements.

Cam Davis, who won the Rocket Mortgage Classic last week for his first PGA Tour victory, was ahead of Kaymer in the world ranking. He had to turn down his spot as a reserve because he was unable to travel unrelated to COVID-19 measures.