Tonali and on-loan Aston Villa forward Nicolo Zaniolo are being investigated by the Turin Public Prosecutor’s Office.

Reports in Italy claim it is in relation to an investigation into illegal betting.

The pair were sent home from the Italy national team last week and could face a hefty fine and possible suspension if they are found guilty.

The 23-year-old has returned to training with the Magpies ahead of the weekend clash with Crystal Palace and his agent Giuseppe Riso says he is fighting the biggest battle of his life.

In an interview with the Times, Riso said: “Sandro is shocked. I hope this experience will help save his life and also the lives of others with his same addictions, including all those young people who are starting to struggle with this addiction.

“Sandro is playing the most important game of his life, against gambling addiction; he won a lot of big games in his life and I’m sure he’ll win this one too.

“Sandro is training and is available for selection. Technically he can play on Saturday. He trained yesterday – he said that one hour and a half on the field helped him take his mind off the whole situation and, once again, Newcastle has been very supportive and trying to help him.”

Juventus midfielder Nicolo Fagioli was handed a seven-month suspension on Tuesday as part of the investigation.