Maria Sharapova and Venus Williams have both withdrawn from their countries' respective Fed Cup ties this weekend. Sharapova has been forced to pull out of Russia's semi-final against Germany in Sochi with a leg injury, the Russian Tennis Federation said on Tuesday. 'I was really looking forward to playing in Sochi and taking part in the Fed Cup,' the world No 2 said. Russian Maria Sharapova has pulled out of this weekend's Fed Cup semi-final with a leg inury . 'For me, it would have been the first time I would have had the opportunity to play in the city where I grew up. 'My team and I specially changed my timetable so that I could represent my country in the semi-final. 'However, unfortunately I picked up a leg injury and it did not allow me to be in the best condition to get ready for this tie,' Sharapova added. The 27-year-old's last appearance was in the Miami Open at the end of March, where she lost in the second round to world number 97 Daria Gavrilova in straight sets. Sharapova (left) shakes hands after losing to compatriot Daria Gavrilova in straight sets in Miami . Anastasia Myskina is the Russia Fed Cup captain . She only returned to practice a few days ago after picking up an injury during in Miami. 'I need to be at the top of my game in order to help my team and play to the best of my ability in the Fed Cup semi-finals against such strong opponents. Unfortunately, I didn't have enough time to prepare,' she said. Sharapova is also a doubt for the WTA Stuttgart Open, which starts on April 20, where she would be defending her title. Sharapova helped Russia beat Poland in the Fed Cup first round in February, where she won both her singles matches. Anastasia Pavlyuchenkova, Svetlana Kuznetsova and Elena Vesnina have all been picked for Russian, with captain Anastasia Myskina now having to find a replacement for Sharapova. Myskina, who won the French Open in 2004, said she had been in constant contact with the Russian number one. 'Over the last few days, I have spoken with Maria and her team a lot,' Myskina said. 'Unfortunately her condition will not allow her to play for the national team. Maria did everything she could to try and play in Sochi. However, at the moment, she just isn't ready. 'I believe in the strength and ability of our team and am really looking forward to the semi-final,' Myskina added. Williams, meanwhile, has withdrawn from the USA team for the World Group play-off because of a personal matter. Venus Williams has pulled out of the USA's World Group play-off against Italy due to personal reasons . The United States Tennis Association says Williams will be replaced by 57th-ranked Lauren Davis. The American team is led by top-ranked Serena Williams and also includes No. 45 Alison Riske and No. 65 Christina McHale. The Italian team includes No. 15 Sara Errani, No. 26 Flavia Pennetta, No. 36 Camila Giorgi and No. 55 Karin Knapp. The Italians are without Roberta Vinci, who has an inflamed right elbow. The best-of-five series will be played outdoors on red clay at the Circolo Tennis Brindisi. Venus's younger sister Serena will lead the American team on the red clay at the Circolo Tennis Brindisi .
Maria Sharapova has been forced to withdraw with a leg injury . Russia host Germany in the Fed Cup semi-finals in Sochi this weekend . Venus Williams has also pulled out because of a personal matter . The USA travel to face Italy in a World Group play-off in Brindisi .