Everton legend and current academy coach
The 52-year-old, who as a player featured heavily in the club's success of the mid-1980s, will undergo surgery this week and is expected to be absent from Finch Farm for some time.
"It's not ideal but I have to remain positive," said Sheedy.
"After a period of rehabilitation I will return to my coaching role at Everton."
Sheedy was keen to highlight the importance of people being aware of getting an early diagnosis if they experienced any problems.
"There is a history in the family," he told evertonfc.com.
"It's so important that people don't ignore the early signs and symptoms and don't be afraid to consult a GP."
Sheedy, a former
English Premier League
Rafael Benitez quietly slipped out of Chelsea as the UEFA Europa League winner ended its season with a 5-3 friendly loss to Manchester City at Yankee Stadium.