Real Madrid skipper Sergio Ramos reportedly had to step in to defuse a training-ground row between Marcelo and under-fire boss Santiago Solari.
Club legend Marcelo, who has lost his place to Sergio Reguilon over the past few months, is said to have hit out at his manager in the days leading up to Sunday's clash at Real Valladolid.
Spanish outlet AS reports that Ramos was forced to intervene after his teammate made a crude remark towards Solari.
Despite the altercation, Solari brought Marcelo on for the final stages of the 4-1 win at Valladolid - his first appearance of any sort in close to a month.
The Brazil international, strongly linked with an end-of-season move to Juventus, is not the only player to have fallen out with the club hierarchy over the past week.
President Florentino Perez is alleged to have threatened to rip up Ramos's contract following a heated exchange in the dressing room after the 4-1 home loss to Ajax that killed off Real's campaign.