It is reported that the world number seven, who has a 4-0 Fed Cup singles record so far this year, may be fit enough to play during the second day of action on the hard courts of the Czech capital's O2 Arena.

The absence of the 2011 and 2014 Wimbledon champion, who has played a huge part in her country's five Fed Cup victories in the last seven years, is an unexpected bonus for a US side that will contain three debutants.

The bad news for the Czech Republic follows the blow they suffered earlier this week when former world number one and current world number eight Karolina Pliskova was ruled out with injury.

That means Barbora Strycova will face Sofia Kenin in the opening rubber tomorrow, before Katerina Siniakova, world ranked 31st, plays 63rd ranked American Alison Riske.

Siniakova is due to meet Kenin in the third singles rubber on Sunday before Strycova takes on Riske, and then the world number one doubles pairing of Siniakova and Barbora Krejcikova - making her Fed Cup debut after being drafted in to replace Pliskova - are due to face Danielle Collins and Nicole Melichar.

American captain Kathy Rinaldi has selected newcomers Collins, Kenin and Melichar for a side that is undefeated in five ties in the women's team tennis competition.

The two finalists are the most successful nations in the history of the Fed, formerly Federation, Cup, having won between them more than half of the 55 previous editions.

This is their 13th meeting in the competition.

The US will hope to retain a title it took them 17 years to earn until last year's win over Belarus - but the Czech side have history, and home billing, on their side.

The American outfit are without their top names such as Serena and Venus Williams and Sloane Stephens.

This may be the last final of its kind, as the International Tennis Federation announced in August that it plans to establish a 16-team standalone Fed Cup tournament in a similar move to the recent overhaul of the men's Davis Cup.