Gary Neville believes that Frenkie de Jong should "consider legal action" against Barcelona.
The Netherlands international is a target for Manchester United, who have reportedly agreed a fee with Barca for the former Ajax midfielder.
However, De Jong is supposedly keen to remain at Barca, while it has also been claimed the Spanish club owe the 25-year-old €20million in wages.
That is after De Jong deferred his wages in order to help Barca deal with their financial difficulties during the COVID-19 pandemic.
Yet in spite of their financial issues, Barca have brought in a number of big-money signings this transfer window, including Robert Lewandowski from Bayern Munich and Raphinha from Leeds United.
And United great Neville believes that De Jong should consider taking Barcelona to court over their failure to pay him the wages he deferred to help out the club.
He tweeted: "De Jong should consider legal action v Barcelona and all players should be behind him!
"A club spending fortunes on new players whilst not paying the ones they have under contract their full money is immoral and a breach."
He also called upon FIFPRO, the representative organisation for professional footballers, to take action against what Neville calls "bullying."