The five-time Grand Slam winner, currently ranked No 2 in the world, must compete in the women’s team event if she wants to bid for gold at the Rio Olympics next year.
Sharapova, 27, made a decisive Fed Cup showing in February when she helped Russia beat Poland in the opening round in Krakow in what was just her fourth appearance in the tournament since her 2008 debut.
Myskina added that in addition to Sharapova and four-time Grand Slam winner Svetlana Kuznetsova, the world No 25, Anastasia Pavlyuchenkova, 38th in the WTA rankings, will also play along with world No 71, Elena Vesnina.
Four-time champions Russia endured a disappointing 2014 season when they were hammered 4-0 by Australia in their opening round clash.
The match, on the red clay courts of Adler Arena, will take place on April 18-19 and will be the fifth meeting between the two nations with Russia holding a 3-1 lead in their head-to-head record.
However, Germany, two-time Fed Cup winners in 1987 and 1992, won 3-2 in their last meeting between the two sides in the 2002 World Group first round.
The Czech Republic host France in the second semi-final in Ostrava.