Maria Sharapova has played only four Fed Cup ties, but her presence on the court could make all the difference as Russia take on holders the Czech Republic in the 2015 final at the weekend.
The 28-year-old world No 4 will likely face sixth-ranked Petra Kvitova and ninth-ranked Lucie Safarova, the left-handed duo who have led the Czechs to three Fed Cup titles from the last four editions.
"It's a great way to finish off the year playing with two of the best players," said Sharapova, a five-time Grand Slam winner, who was sidelined with leg and arm problems from July to October.
Sharapova returned to action at the WTA Tour Finals last month, where she lost to Kvitova in the semifinals – after losing to Safarova at the French Open in June.
"I know how difficult an opponent they are and it will be a great challenge for me," said Sharapova, called up alongside 23rd-ranked Ekaterina Makarova, Anastasia Pavlyuchenkova (28) and Elena Vesnina (111).
"We are coming into these finals as the underdogs," she added. Equally high-spirited, the Czech team denied being the odds-on favourite.
"They have the highest-ranking player and a permanent doubles pair" of Vesnina and Makarova, said Czech captain Petr Pala.
"The chances are perfectly even," added Pala, who has also nominated 11th-ranked Karolina Pliskova and world number 41 Barbora Strycova.
The two nations have met five times in the Fed Cup before but three of those meetings were between Czechoslovakia and the Soviet Union.
The Czech team lead their head-to-head record with Russia 3-2, including a victory in the most recent encounter in the 2011 final in Moscow.
Four-time champions Russia will be playing in their 11th Fed Cup final.