This evening Roger Clemens, the greatest pitcher in contemporary baseball, will appear on television and attempt to say it ain’t so – that he hasn’t systematically used performance-enhancing drugs to become an iconic figure in what many Americans regard as the national pastime. His denial comes at a time when the public distrusts professional sportsmen on the question of doping – and if there wasn’t distrust, there is plenty of evidence against the 45-year-old pitcher.

But top sportsmen hire the best lawyers and get to choose their own television interviewer. The questions will be asked by Clemens’s friend, 89-year-old Mike Wallace, for CBS’s flagship news programme, 60 Minutes. At stake is Clemens’s reputation and the good name of the sport at which he excels. Wallace has long been regarded as one of America’s tougher interviewers, but, sitting across from his friend, how persistent and sceptical will he be?

Clemens’s problems began with the publication of the Mitchell Report on December 13. Former senator George Mitchell, who played an important role in the resolution of the conflict in Northern Ireland, had been asked by Major League Baseball’s commissioner, Bud Selig, to produce a comprehensive report into the use of banned performance-enhancing drugs.

Mitchell spent 21 months on the case and his report runs to almost 500 pages. Although it had access to a limited amount of information and received cooperation from few of those on the inside, he still managed to show baseball as a sport poisoned by illicit drugs and populated by players and their representatives who feel entitled to break the rules.

It was significant, but not surprising, that he received virtually no help from the players. This was a report they did not want, and their fears were confirmed by its content. Mitchell named 89 Major League baseballers as being involved in doping, three times more than had been caught in six years of testing by the sport itself. That is staggering when one considers the lack of cooperation given to the inquiry and how few leads there were.

He got lucky in one respect. Federal investigators were alerted to the activities of a steroid supplier, Kirk Radomski, who was buying banned drugs over the internet. A raid on his home unearthed names and corroborative details about his customers, who included several high-profile baseball players. Radomski also supplied a man called Brian McNamee, who was a fitness and conditioning coach at the New York Yankees and personal trainer to Clemens.

When the Feds got to McNamee, he was ready to talk. Given that his story involved a man whom some describe as the sport’s greatest-ever pitcher, his evidence would have far-reaching implications. McNamee met Clemens when he worked as a fitness coach for the Blue Jays in Toronto. One evening the player spoke to him, said he was not comfortable injecting himself and asked if the trainer would help. That began a relationship described in great detail by McNamee to Mitchell.

According to McNamee, it involved him buying steroids and growth hormones from Radomski and administering them to Clemens. He recalled Clemens requesting that he inject him with the anabolic steroid Winstrol. McNamee knew the substance was Winstrol because it said so on the label.

In 1999 Clemens was traded to the New York Yankees. A year later McNamee joined the Yankees as a fitness trainer. He got the job on Clemens’s recommendation.

McNamee recalled that during the 2000 season Clemens made it clear he was ready to use steroids again. During the latter part of the season, he says he injected Clemens in the buttocks four to six times with testoster-one. During this time, he also allegedly injected the pitcher with human growth hormone on four to six occasions. Each time, McNamee bought the drugs from Radomski.

They didn’t often speak about performance-enhancing substances and Clemens didn’t pay directly for the drugs bought by his trainer. Instead, he gave him money that more than covered the price of the drugs. McNamee says he bears no ill-will towards Clemens, who always treated him fairly and paid him generously. When McNamee’s name was mentioned in relation to the investigation into Radomski, Clemens continued to support his trainer.

Federal investigators have said that McNamee has told the truth to his financial cost and he gave his evidence in the knowledge that if it was proved that he lied, that would be considered a felony. Mitchell was keen to speak to Clemens about the allegations, but like so many of his peers, he declined to speak.

It is ironic that Clemens’s high-profile lawyer, Rusty Hardin, now says there were people Mitchell should have spoken to but didn’t. Hardin was thinking about witnesses who might have disputed McNamee’s claims or lessened his credibility, but he didn’t mention why his client chose not to speak to Mitchell. Who better to tell him that McNamee’s story isn’t accurate than the player himself?

There are difficulties for Clemens, not least the evidence of his teammate Andy Pettitte. McNamee, who was also personal trainer to Pettitte, told Mitchell that he injected the player with human growth hormone on two to four occasions. Pettitte has since admitted he was injected with human growth hormone by McNamee. It begs the question: why would McNamee lie about Clemens and tell the truth about Pettitte?

In his interview with Wallace, which was recorded last week, it is believed that Clemens admits to being injected by McNamee, but says the substances were B12 vitamins and the painkiller lidocaine. Not a lot of people are rushing to give him the benefit of the doubt. Sport has been down this troubled path too many times recently.

The judge in the Marion Jones case is seeking extra information, and she may serve longer than the expected six-month prison term. The former Olympic champion is hoping that she won’t be forced to serve jail time. The trouble that she is now dealing with stems not from the performance-enhancing drugs she used, but from the fact that she lied under oath about her doping.

Another iconic figure in baseball, Barry Bonds, stands accused of lying about his use of drugs. Bonds, who holds the all-time record for home runs, admits being injected by his trainer Greg Anderson, but insists the substances were not banned. As in the case of Clemens, the tide of public opinion runs against him.

What their stories, and the saga of Marion Jones, tell us is that when an athlete rises to the very top and achieves the recognition and salary commensurate with his or her status, it is hard to tell the truth.

When the Canadian sprinter Angella Issajenko testified before the Dublin Inquiry in 1989, she said the first three reactions of the doper were to, “deny, deny, deny”.

True in the Ben Johnson era and true today.