GRIMSBY have been fined by the EFL for fielding an ineligible player in their shock League Cup victory over Manchester United last week.

The Mariners beat United 12-11 in a penalty shoot-out, having led 2-0 in normal time before being pegged back.

The EFL said the breach related to Clarke Oduor, who came on as a 73rd-minute substitute.

The player’s registration was submitted at 12.01pm on the day before the match, shortly after the 12pm deadline required in accordance with this season’s competition rules.

The League Two club have been fined £20,000, with £10,000 suspended until the end of the season which would be triggered if they fielded an ineligible player in any EFL competition.

The EFL said Grimsby self-reported the breach once they discovered the error the day after the match.

The EFL said the issuing of a fine followed precedent after a comprehensive review of all the evidence and considering prior decisions in respect of offences in the League Cup.

The EFL’s board determined the club’s non-compliance was not deliberate, with no intention to deceive or mislead.

The Mariners released a statement acknowledging the sanction, and said the delay in meeting the deadline had been due to a computer problem.

“We accept the fine imposed and fully recognise the importance of adhering to competition rules and regulations,” the club said.

“This mistake was not deliberate, and the club acted transparently by self-reporting the breach as soon as it came to light.”

Manchester United did not wish to comment when contacted by the PA news agency.