New Stags chief executive John Hemmingham, speaking on BBC Radio Nottingham ahead of the match against Cambridge, said that the problems over a Mansfield player's registration had been uncovered by a Grays reporter.

And with O'Connor joining the Stags from Grays at the start of the season, that would appear to confirm Chad's first reports on Wednesday that the striker was involved in the probe.

The Football Conference had revealed on Wednesday afternoon that it was investigating a club for breaching its rules in the first two matches of the season.

And first reports suggested that the club was the Stags, despite denials from Field Mill, with the club facing a possible punishment of being deducted points and a fine.

Then on Thursday afternoon the Stags released a statement confirming the investigation, saying it had received official contact from the Conference about the issue.

The Mansfield Town FC statement on Thursday read: "We can now confirm that we have had dialogue with the Football Conference relating to player registration/signings.

"At this point in time, we have no further information on the matter and are unaware that any regulations have been breached.

"We will issue a further statement once we know the full details of the matter."

Although aware of the rumours over an investigation, boss Billy McEwan would only say on Thursday afternoon: "All we want to do is concentrate on Saturday's game - anything else is irrelevant so it's not an issue. We are only concerned with what happens on the field of play and geting on with our jobs."

It is not clear how the player, believed to be Aaron O'Connor, may have been ineligible - whether it concerned his registration not being received by the Conference in time to play the two matches, or some other matter.

However, there is no suggestion that the club deliberately broke any rules.

Mansfield chairman Andy Perry told Chad on Wednesday evening that he had been made aware of the rumours only a few hours earlier and was still trying to speak to Conference officials.

"I don't know anything about us breaking any rules, other than these rumours. We are making enquiries with the Conference," he said.

But Dennis Strudwick, general manager of the Football Conference, said on Thursday morning that the club involved in the probe had been made aware of the situation.

Mr Strudwick said it was not known how long the investigation would take and declined to speculate any further on the club involved or possible punishment.

He told Chad: "We check all player registrations every week as a matter of routine. That is when we discovered there may be a problem.

"This investigation will take as long as it takes, hopefully no more than a couple of weeks."

It is rumoured that the player in question may be striker O'Connor, who was signed in a flurry of transfer activity the day before the opening match of the season at Ebbsfleet.

O'Connor had been offered a new contract by Grays, before agreeing to come to Field Mill.

He started the opening match at Ebbsfleet and also made a substitute's appearance the following Tuesday in the win over Histon.

However, the identity of the player is still speculation with the only confirmed information the fact that an investigation into an ineligble player at Mansfield Town is underway.