The Football Association (FA) are investigating whether Newcastle United midfielder Sandro Tonali breached betting rules after joining the Premier League club in the summer, a source has told ESPN.

The Italy international was sanctioned with an 18-month ban last month by the Italian Football Federation, eight months of which will be commuted to alternative treatment after an agreement was reached with the Federal Prosecutor's Office.

FIFA said it granted a request by the Italian federation to apply the ban worldwide.

The 23-year-old joined Newcastle from Serie A side AC Milan in July for a reported fee of 70 million ($75.15m), but he will miss the rest of the season as well as next summer's Euro 2024 tournament, if Italy qualify.

Tonali's breaches of rules on betting on matches caught Newcastle by surprise, and the Premier League club is conducting an internal investigation into the midfielder's transfer, the team's sporting director Dan Ashworth has said.

"It was a massive shock, a massive surprise. Dealing with it was new to all of us," Ashworth told reporters. "First and foremost, Sandro is a human being. Everyone in this room has done things we shouldn't have done or things we regret.

"He was a big signing for us. We didn't expect it. You look at yourself. Could I have done better? Could we have known? Should we have known? You look at your processes. I have been doing this for 16 years and it has never happened before."

When asked if there was a chance Milan could have known about it at the time of the transfer, Ashworth said: "It's really difficult for me to get into what other clubs do or don't know.

"All we can do is look at our own internal investigation and internal process. It's a really difficult question for me to answer, I just don't know."

Tonali's agent last month said the player was suffering from a gambling addiction.

Ashworth said the FA are aware of the happenings, and the club is cooperating.

"In terms of a further ban from the FA, I can't look into the future, I can only deal with the present and the facts," he added.

Sixth-placed Newcastle host Arsenal in the top flight on Saturday, followed by a Champions League trip to Borussia Dortmund next week. Ashworth said Newcastle will "welcome" Milan when they host them in Europe's elite club competition at St James' Park in December.

Information from Reuters and ESPN's Mark Ogden contributed to this report