Lazio coach Vladimir Petkovic says Mauro Zarate is training alone after excluding himself from the rest of the squad.
The striker has only made one Serie A appearance this season and will not be considered for the Coppa Italia match against Siena, after failing to report for the match against Inter on Saturday.
And Petkovic revealed the 25-year-old has asked to be left out of the team as he looks likely to leave Stadio Olimpico in the January transfer window.
"He's put himself out of things. He won't be called up for tomorrow night's encounter," he told a press conference.
"He's asked to be placed to one side and is currently training on his own. We'll see what happens next."
It was thought the former Al-Sadd forward would be used for the cup encounter after playing in all of his side's Europa League games, but it now seems he has played his final match for the club.