The 23-year-old could now be set for an even further period of time on the sidelines.
In a statement, the FA said: "Sandro Tonali has been charged with misconduct in relation to alleged breaches of The FA's betting rules.
"It's alleged that the Newcastle United midfielder breached FA rule E8 50 times by placing bets on football matches between August 12, 2023 and October 12, 2023. Sandro Tonali has until April 5, 2024 to respond."
The Magpies stated: "Newcastle United acknowledges a misconduct charge received by Sandro Tonali in respect of alleged breaches of FA Betting Rules.
"Sandro continues to fully comply with relevant investigations and he retains the club's full support. Due to this ongoing process, Sandro and Newcastle United are unable to offer further comment at this time."