Manchester United's players are angry over how David de Gea was treated by the club this summer.
The veteran shot stopper was let go after his contract expired, with Andre Onana signed from Inter Milan to replace him.
Per The Sun, United players are unhappy at how the club initially agreed a deal with De Gea, but then went back on their word.
The keeper had verbally agreed to lower his 375,000 a week wages and sign an extension.
However, United went back on that deal, stating De Gea must accept a further wage reduction to stay.
He then decided not to continue negotiating and United let his deal expire, which has upset many senior players.