Grimsby Town have been fined £20,000 for fielding an ineligible player in their famous Carabao Cup win over Manchester United.

The Mariners knocked out the Premier League club on penalties after the tie finished 2-2 after 90 minutes.

The League Two side brought on midfielder Clarke Oduor, who had joined on loan the day before from Bradford City, as a substitute, but later realised he had been registered one minute and 59 seconds after the 12:00 BST deadline.

Oduor came on in the 73rd minute and had his penalty saved by Andre Onana in the shootout, but Grimsby won 12-11.

In a statement, the EFL said, external Grimsby reported the breach themselves and the "club's non-compliance was not deliberate with no intention to deceive or mislead".

They must pay £10,000, with the remaining £10,000 suspended until the end of the season.

Manchester United, who were told of the situation on Monday, will not be pursuing a return to this season's competition.

The EFL said the board's decision to issue a fine "followed precedent" and was taken after a "comprehensive review of all the evidence and considering prior decisions taken in respect of offences in the League Cup".

On the three previous occasions ineligible players have been fielded in the competition, the clubs making the error have also been fined.

Liverpool, Accrington Stanley and Sunderland were the clubs involved, and like Grimsby, they also all won their ties.

David Artell's side will face Championship strugglers Sheffield Wednesday in the third round of the competition later this month.

"The registration was submitted to the EFL at one minute past the deadline, and the issue was not immediately identified by the club due to a computer problem being experienced," read a Grimsby statement., external

"We accept the fine imposed and fully recognise the importance of adhering to competition rules. This mistake was not deliberate, and the club acted transparently by self-reporting the breach as soon as it came to light.

"Since this incident, we have undertaken a thorough review of our processes and implemented strengthened measures to ensure it cannot happen again.

"We thank the EFL board for recognising our co-operation and intent."

When has this happened before?

Jonty Colman

BBC Sport journalist

In October 2019, Liverpool were fined £200,000, of which £100,000 was suspended, for fielding Pedro Chirivella in an EFL Cup third-round win against MK Dons.

Chirivella did not have international clearance to play in the competition, but the EFL said it "wasn't appropriate" to remove Liverpool because of "mitigating factors".

In 2016, Accrington received a suspended fine of £5,000 for fielding Janoi Donacien in their first two matches of the season - a League Two victory against Doncaster Rovers as well as a first-round EFL Cup win over Bradford City.

Donacien had not received international clearance following the expiration of a loan spell at Newport County in the previous season.

In August 2013, Sunderland were fined £25,000 for fielding Ji Dong-won, who was ineligible, in an EFL Cup win against MK Dons.

Sunderland were also fined by the Premier League for fielding the ineligible Ji multiple times during that season.

The EFL operates to a different set of rules to the Football Association, which has previously removed teams from the FA Cup because of player ineligibility.

In November 2023, Barnsley were removed from the FA Cup for fielding an ineligible player in their first-round replay win over non-league Horsham.

Elsewhere, Real Madrid were removed from the Copa del Rey - Spain's national cup competition - in December 2015 after fielding Denis Cheryshev, who should have been serving a suspension, against Cadiz.