World No 1 Iga Swiatek has decided to not play for Poland in next month's Billie Jean King Cup finals due to scheduling issues and has criticised tennis' governing bodies over their handling of the tournament calendar.
Swiatek, who last month won the US Open, had helped Poland progress to the Glasgow finals in April but the tournament will be held from November 8-13, just one day after the season-ending WTA Finals which will be held in Fort Worth, Texas this year.
"I was thinking it through a lot and discussing it with my team all over again, but I will not be able to play at the Billie Jean King Cup in Glasgow. And it makes me sad," the three-time Grand Slam champion said on Instagram.
"I'm very sorry, because I play for Poland whenever it's possible and I always give it my best. Playing in Poland this year was an honour and I hoped to do this again at the end of the season.
"I'm disappointed that tennis governing bodies didn't come to an agreement on something as basic as the calendar of tournaments, giving us only one day to travel through the globe and changing the time zone."
While the WTA Finals are organised by the women's tennis body, the Billie Jean King Cup – previously known as the Federation Cup – is run by the International Tennis Federation (ITF).
"This situation is not safe for our health and could cause injury. I'm going to talk to the WTA and ITF in order to change something," Swiatek, 21, added.
"This situation is difficult not only for the players like me, but mainly for the tennis fans that support our sport."
The Billie Jean King Cup will have 12 teams competing in four round-robin groups of three teams each, with the group winners moving to the semi-finals. Poland are in Group D with the Czech Republic and the United States.
Swiatek is, however, confirmed to play in the new World Tennis League in Dubai. The tournament, held at the Coca-Cola Arena from December 19-24, will feature the best men's and women's players playing two-set matches across both singles and mixed doubles matches.
Novak Djokovic, Nick Kyrgios, Alexander Zverev, Simona Halep, and Elena Rybakina will also compete in the tournament.