The former England Under-16 international finished his career with spells at the likes of AFC Telford United, Hinckley, Blyth Spartans and Whitby before retiring in 2015.
Paying tribute to Farrell, AFC Rushden & Diamonds said in a short statement on Twitter: “We are saddened to hear about the passing of former RDFC striker Craig Farrell.
“Our thoughts are with his family at this time.”
Aaron O’Connor, who played alongside Farrell at Nene Park, also paid his own tributes on social media, writing: “’I’m still in total shock, but gotta send a tribute to my friend Faz.
"Still can’t believe it. We shared some of the best times together, times I’ll never forget. R.I.P brother. I’ll never forget you.”