Southampton were thrown out of Saturday’s Championship playoff final - the richest game in world football - after being found guilty of spying on semi-final opponents Middlesbrough in one of the harshest punishments imposed in the English game.
Middlesbrough have now been reinstated and are due to face Hull City at Wembley on Saturday. However, Southampton have appealed against the decision by the Independent Disciplinary Commission, with a final ruling expected later on Wednesday.
"On the appeal itself: we accept that there should be a sanction. What we cannot accept is a sanction which bears no proportion to the offence," Parsons said in a statement.
"Whereas Leeds United was fined 200,000 pounds ($267,940) for a similar offence, Southampton has been denied the opportunity to compete in a game worth more than 200 million pounds and one which means so much to our staff, players and supporters.
"We believe the financial consequence of yesterday's ruling makes it, by a very considerable distance, the largest penalty ever imposed on an English football club."
Even a single season in the Premier League, followed by immediate relegation, is estimated to be worth around 200 million pounds over three seasons through broadcast revenue, sponsorship and parachute payments.
In 2019, Leeds were fined 200,000 pounds and reprimanded for spying on Derby County. Then-Leeds boss Marcelo Bielsa admitted his staff had watched all the club's opponents in training that season.
Parsons listed examples of other sanctions, such as Luton Town's 30-point deduction in 2008-09 for a club in League Two but with "no comparable revenue at stake" as well as Derby's 21-point deduction in 2021 that cost them their Championship status.
"We say this not to minimise what occurred at this club, which we have accepted was wrong. We say it because proportionality is itself a principle of natural justice," Parsons added.
"The Commission was entitled to impose a sanction. It was not, we will argue, entitled to impose one that is manifestly disproportionate to every previous sanction in the history of the English game."