The sister of Brazil defender Maicon insists his early return from international duty was not due to indiscipline but because the full-back felt he could not give everything for his country.
The 33-year-old Roma player was sent home on Sunday.
"We'd like to thank the player for his service to the national team, but today he has been released by the coaching staff," the Brazil national team's general coordinator Gilmar Rinaldi said.
His place in the squad for a friendly against Ecuador in East Rutherford has been taken by Monaco's Fabinho, but mystery surrounded Maicon's exclusion.
"It was an internal problem and I won't respond to questions about it, and I would prefer it if you don't ask any questions," Rinaldi added. "Fabinho from Monaco is on his way and we're waiting to find out when he will arrive."
Maicon's sister, Erla Sisenando, insisted the player "left with his head held high."
"There were no problems and he's spoken with [coach] Dunga," she said, according to Corriere dello Sport. "There weren't any physical problems because he's fine and could play for anybody right now, but it's more a question of him not being able to give 100 percent for Brazil."
Maicon played the full 90 minutes for the Selecao in their 1-0 friendly victory against Colombia on Friday night, despite not having trained fully for Roma in preseason.
His early return will nevertheless come as a boost to Roma coach Rudi Garcia, who would otherwise not have seen the defender until Thursday, just two days before the Giallorossi face Empoli in their second match of the Serie A season.
Roma are then in action against CSKA Moscow on their return to the Champions League next Wednesday.