Mr Sidhu had allegedly hit a 65-year-old man, Gurnam Singh, on the head during an argument on a road in Patiala on December 27, 1988. Gurnam Singh died of a haemorrhage.
A trial court had discharged Mr Sidhu, but the High Court reversed it and held him guilty of culpable homicide in 2006. He was given three years in jail. In 2007, the Supreme Court suspended Mr Sidhu's sentence and granted him bail after he appealed his conviction by the Punjab and Haryana High Court. The suspended sentence enabled him to contest the Lok Sabha bypolls from Amritsar.
On Thursday, the Punjab government told the top court that Mr Sidhu's conviction should be upheld.
The 55-year-old cricketer-turned-politician had quit the BJP in 2016 and joined the Congress last year.Captain Singh's government, officials say, had no choice but to oppose its own minister in court. After arguing against Mr Sidhu in the high court, it could not change its stand before the Supreme Court, they said.
Captain Singh, however, hoped that the judge would take into account Mr Sidhu's "contribution to the society and the country" in his final verdict.
"Though the government could not have taken any other stand in the apex court, other than what it had been taken in the trial and high court earlier, Sidhu deserved the court's consideration," said the Chief Minister, who is drawing flak for letting down his own minister.
He added, "Had we done so (defended Mr Sidhu), we would have been accused of lying either now or earlier."Facing criticism over his alleged dislike for Mr Singh and the way his case was handled by the Punjab government, Captain Singh, according to news agency IANS, said, "Sidhu, whom I have known since he was a child, was a person totally above board, who went out of the way to help people in need."
With inputs from agencies