Sharapova, who needs a Roland Garros title to complete a career Grand Slam, saw her meteoric rise halted by shoulder surgery which sidelined her for almost a year until mid-2009.
Shvedova, meanwhile, injured her knee while on Hopman Cup duty for Kazakhstan in January 2010, and missed the Australian Open.
Although she won the women’s doubles at Wimbledon with Vania King, her singles ranking collapsed to 206 from a place in the Top 30.
That condemned her to play qualifiers at this French Open and if she makes it to the last four, she will be the first qualifier to reach the semi-finals.
Sharapova, the World No 2, is now the overwhelming favourite to capture the title after the early exits of top seed Victoria Azarenka, defending champion Li Na and former winner Serena Williams.
Her 2004 Wimbledon triumph, 2006 US Open victory and 2008 title at the Australian Open all came before her shoulder surgery.
“So now when I’m playing, I really feel like I’m much more positive. Overall, I see my career much more positive than I looked at it back then, especially during the tough days,” said Sharapova, who for the first time faces Estonian 23rd seed Kaia Kanepi for a place in the last four.
Shvedova, now the world number 142, was a quarter-finalist in Paris in 2010, but she admitted that the last year had been tough.
“I had the injury and surgery right after Australia. I was recovering a very long time and when I came back my knee was bothering me for half a year,” said the 24-year-old Moscow native.