Yuvraj, 29, who was declared the man of the tournament after the World Cup win at home in April, had opted out of the upcoming one-day series against the West Indies for health reasons.
"During the World Cup, Yuvraj found himself constantly troubled by bouts of coughing and vomiting," his mother Shabnam Singh said in a statement.
She said Yuvraj initially ignored the problem, assuming it was due to stress and did not want anything to distract him.
"When the problem persisted after the World Cup, we decided to seek medical advice... scans then showed us that Yuvraj was dealing with something really serious. A golf-ball size lump (was) found over his left lung," she said.
"Further reports have indicated that the tumour is non-malignant and non-threatening and can be treated through proper medication and therapy... Yuvraj is now in a much better state and on his way to a full recovery."
The aggressive left-hand batsman and spin bowler had gone through "a very hard time" but was now focused on returning to the field, Shabnam added.
Yuvraj wrote on his Twitter page that he was "overwhelmed" by the support he had received. "I am absolutely fine, just need to get match fitness and training. Will be back soon," he said.
Yuvraj, who played in two of three Test matches against the West Indies this month in Delhi and Kolkata, was not picked for next month's Test series in Australia.
He hopes to be back in action for the subsequent one-day tri-series Down Under, also featuring Sri Lanka, which begins on February 5.
Yuvraj, who made his international debut in 2000, has played 37 Tests, 274 one-day internationals and 23 Twenty20 matches for India.
He was part of India's champion team at the inaugural World Twenty20 in South Africa in 2007, where he smashed England fast bowler Stuart Broad for six sixes in one over.
The explosive hitter has been the lynchpin of India's middle-order in limited-overs cricket, although he has not met with the same success at the Test match level.
During the World Cup campaign this year, Yuvraj scored 362 runs and grabbed 15 wickets in nine matches to carry off the man of the tournament award.
At the Test level, Yuvraj has scored 1,775 runs at an average of 34.80 with three centuries and 10 fifties.
Hope he recovers soon and be fit for ODI series against Australia.
