Deeney suspects gay footballers are worried about the scrutiny that would follow if they reveal their sexuality while still playing.
But the 31-year-old claims one top player coming out would lead to others following their lead.
Talking on the BBC’s Grounded with Louis Theroux podcast, Deeney said: “I would go on record saying that there is probably one gay or bi-person in every football team. They’re there, they are 100 percent there.
“I think people that are gay or from that community definitely are very worried about having to shoulder the responsibility of being the first. I think once the first comes out, there would be loads.
“If he come out and said it, I genuinely believe you would get in the first week at least 100 people that went ‘me too’. Just because they don’t want to be the face of it.”
Former Norwich and Nottingham Forest striker Justin Fashanu, who declared he was gay in 1990 and died in 1998, remains the only openly gay male footballer in British history.
Despite acknowledging some players would fear criticism, Deeney, who is preparing for the Premier League’s return on June 17, believes the current era is a good time for sportsmen to declare if they are gay.
“I think there is now a bigger platform than ever to be a gay athlete of any nature,” he said.
“I also wonder, why people finish football, rugby, whatever the sport it might be, and then go ‘I am gay’… I feel like it must be a real heavy load to carry throughout all your whole sporting career.”