Yorkshire's chief executive Stewart Regan has issued an open letter to the county's supporters admitting the club have damaged the game's reputation.
Regan has apologised to members and fans in the wake of Yorkshire's expulsion from the Twenty20 Cup for fielding
17-year-old off-spinner Azeem Rafiq, an ineligible player.
Yorkshire's appeal against the England and Wales Cricket Board's decision to throw them out of the competition will be heard at 2.30pm in Taunton today. Regan has admitted the club's culpability in failing to properly register Rafiq, who does not have a British passport and is not registered to play first-team cricket, leading to the 11th-hour abandonment of last Monday's quarter-final against Durham at Chester-le-Street.
Regan's letter, posted on the Yorkshire CCC website, reads: "On behalf of the board of Directors of The Yorkshire County Cricket Club I write to express my sincere apologies for events leading to the postponement of Monday evening's Twenty20 Cup Quarter Final between Yorkshire Carnegie and Durham Dynamos.
"I can honestly say that the club did not intend to gain any unfair competitive advantage by playing Azeem Rafiq in our final group match against Nottinghamshire Outlaws.
"The failure to register the player or check his final eligibility for registration has led to the harshest penalty possible, that is expulsion from the competition.
"The club will learn from this mistake and procedures have already been put in place to prevent this happening again.
"We are all extremely embarrassed that we have damaged the game's reputation and I felt it appropriate that we send you our apologies."
Regan, who believes Yorkshire's punishment is "manifestly disproportionate" to the seriousness of their offence, has insisted he will not resign following a blunder that looks certain to cost Yorkshire the chance of taking part in the £2.5m Champions League.
At an ECB hearing last Thursday, a disciplinary panel found Yorkshire guilty of "a serious breach of the regulations" and found Yorkshire were aware, no later than early 2007, that there were questions as to Rafiq's immigration status and said the club had been put on notice to properly check his eligibility.
Yorkshire are expected to claim today that Yorkshire Schools, which falls under the remit of the Yorkshire Cricket Board, were the recipients of that warning as opposed to the county club.