Celebrated Indian goalkeeper Subrata Paul is staring at a career-threatening four-year ban after failing a dope test but has vowed to prove himself innocent by going for the confirmatory 'B' sample test.

All India Football Federation General Secretary Kushal Das said Paul, an Arjuna Awardee, flunked an out-of- competition test in March.

"Yes, Subrata Paul's 'A' sample has returned positive for a banned substance and he can be banned for four years if his 'B' sample also tests positive. The urine sample was taken by NADA on March 18 when the Indian team was in the national camp in Mumbai. All the players were tested during that camp," Das said.

"Actually, I am shocked at this development. Not many football players have failed dope tests. I never thought a player of his stature would fail a dope test," he added.

Under WADA rules, the National Anti-Doping Agency will have to inform the player as well as the federation about the dope result. The player has the right to request for a confirmatory 'B' sample test. He will be put under provisional suspension pending his 'B' sample test.

Under new WADA rules, a first-time dope offender will serve a maximum period of four-years.

The 30-year-old Paul said he will go for the 'B' sample test and claimed that he will prove his innocence.

"I am shocked at this news that I failed a dope test. I have not got any official communication from the NADA or the AIFF. I am getting to know about this from the media. I will prove my innocence as I have played the game with honesty and integrity in my career of more than 10 years now," Pal said.

"I will request for the 'B' sample test as I believe that I have not done anything to fail a dope test. All the players were tested during the Mumbai national camp and I never thought that my sample will return positive," he added.

Paul, who made his India debut in 2007 and went onto represent the country 64 times till 2015, said he has achieved most of whatever he had set out for in his career. And there is no reason for him to do cheat and risk tarnishing his reputation.

"The AIFF officials, the fans, fellow players and the media knew that I have been an honest player throughout my career. I have built up a reputation and I have achieved a lot in my career, for my clubs and for my country. At this point in time of my career, I do not need anything like taking a banned drug to enhance my performance.

"So, I am shocked at this development. My reputation is at stake and I want to clear my name. That is why I will go for the 'B' sample test," he said.

Paul, from West Bengal, has been one of India's finest goalkeepers. He was the number one goalkeeper during the time Englishman Bob Houghton was at the helm of affairs as India coach and Bhaichung Bhutia was the captain.

He played a major role in India winning the Nehru Cup international tournament in 2007 and 2009.

Paul's heroic performances under the bar were also instrumental in India winning the 2008 AFC Challenge Cup in Hyderabad, which led to the qualification for the AFC Asian Cup held in Doha in 2011.

In that tournament, he was referred to by the media as the 'Indian spiderman' due to a series of spectacular saves he made in the three group matches, especially against South Korea.

In the last couple of years, Paul has not been India's No.1 goalkeeper as that position has gone to Gurpreet Singh Sandhu, who currently plays for a Norwegian first division club.

Paul was part of the Indian squad which played against Cambodia in an international friendly (March 22) and against Myanmar (March 28) for the 2019 AFC Asian Cup qualifiers, but did not make it to the playing eleven.

He played for NorthEast United in the 2016 Indian Super League season and he is currently playing for DSK Shivajians in the I-League. He was awarded the Arjuna Award in 2016.

Doping in Indian football is rare. Before Paul, former Mahindra United defender Arun Malhotra was perhaps the first high-profile footballer in the country to be banned after he failed a dope test in 2002. He was stopped from joining the team for the Asian Games in Busan.

In 2011, Nishant Mehra tested positive for a banned substance and was banned by NADA for two years. Later in 2015, Mumbai FC's Dane Pereira tested positive for a banned substance taken by NADA after an I-League match against Royal Wahingdoh at the Cooperage stadium in Mumbai.