Sunderland winger Adam Johnson has been ruled out of action for at least two months with a "serious" shoulder injury.

The 28-year-old suffered the problem during a recent training session.

Johnson is due to undergo further tests on Wednesday evening, but Black Cats boss Dick Advocaat is expecting him to be sidelined for a minimum of eight weeks.

"Adam will go to the hospital for a scan tonight and then we will know exactly what is wrong," he told the club's official website. "It is a serious injury and it will be at least eight weeks."

Johnson started Sunderland's 4-2 defeat to Leicester City on the opening day of the Premier League season.