Mitchell Cole, who had played for Oxford United and Stevenage, was forced to give up the professional game last year because of a rare heart condition.
Hundreds of fans have posted messages on Twitter in response to the news of his death.
The Football League also used the social networking site to pay tribute.
“We are sad to hear former Southend, Stevenage and Oxford player Mitchell Cole has passed away,” it said in a tweet.
“Our thoughts are with his family and friends.”
The Professional Footballers’ Association (PFA) joined the Football League in expressing their condolences.
“The PFA is deeply saddened by the loss of 27-year-old Mitchell Cole, our thoughts are with his friends and family,” it posted on Twitter.
Cole was married to the sister of England international Joe Cole.