The Red Devils, who told the RFL they could not play the match on October 30 because they only had 13 players available, have been penalised £15,000, half of it suspended.
Salford cited player welfare concerns during a period of fixture congestion exacerbated by their progress to the Challenge Cup final.
A club statement said: “Salford Red Devils have been hugely disappointed by the RFL’s decision to impose a £15,000 fine.
“The club made every effort to fulfil all fixtures, with additional recruitment to the squad despite no threat of relegation, and strict adherence to Covid-19 protocols, which prevented rescheduling as a consequence of outbreaks within the Red Devils group.
“Two young players were also promoted from the academy and made their Betfred Super League debuts.
“The decision was made that it would be a risk to the welfare of these players and those who had recently returned from injury to expose them to 80 minutes in opposition to senior players that compete at international level without any possibility of interchanges.
“At a time when other sports have been criticised for their approaches to player welfare, Salford Red Devils are disappointed that the RFL have not supported the stance taken by the club. This will not alter the club’s priorities and approach going forward.”
Warrington were awarded a 24-0 victory and the matter was referred to the RFL compliance department.
The governing body said: “The RFL has to ensure the integrity of its competitions at all times, which includes the fulfilment of fixtures by all clubs.
“However, the level of sanction recognises the unique circumstances that clubs, including Salford, faced during the 2020 season and the co-operation that the RFL received from the club during its investigation.”
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