A wave of sympathy swept the country when his mother said in a statement at the weekend that the left-hander, who turns 30 next month, had a golf ball-sized tumour.
Yuvraj played in the Delhi and Kolkata tests against West Indies this month but will be missing for the five-match one-day series against the same opponents that starts in Cuttack on Tuesday.
"Overwhelmed with your love and support. I am absolutely fine, just need to get match fitness and training, will be back soon," he said on his Twitter account.
"Need some more time to regain 100p (percent) fitness. Nothing serious, need to build up the lost stamina."
One of the cleanest strikers of a cricket ball, middle-order batsman Yuvraj is not a regular member of India's test side but is an automatic choice in their limited-over teams.
Yuvraj was instrumental in India's 2007 World Twenty20 victory in South Africa and hit England fast bowler Stuart Broad for six sixes in an over in one of the matches.
He was also named player of the tournament in India's successful 50-over World Cup campaign on home soil in February, March and April.
The statement from his mother Shabnam Singh said Yuvraj suffered regular bouts of coughing and vomiting during this year's World Cup but ignored them.
As the problem persisted he finally sought medical advice.
"Scans showed Yuvraj was dealing with something really serious. A golf-ball sized lump (was) found over his left lung and doctors advised us to go in for more detailed scans," his mother said.
"Everyone who knows Yuvraj knows he is a fighter and has been very strong and a pillar for the family through this trying period. We are sure that very soon he will be back on the cricket field in India colours."
Posts
