McDonnell bagged 22 goals in his debut campaign for Reds after signing from Croydon last summer.
The forward's departure is another blow to Town's hopes of finding a strike partner for the recently signed Joff Vansittart and comes hot on the heels of Barrington Belgrave's decision to opt for Farnborough Town instead of the Broadfield Stadium.
Belgrave (below), a former Norwich City forward, was released by Nationwide Division Two Southend United, but despite Reds boss Francis Vines being the first to show interest, the 22-year old, who scored 10 goals fom 62 matches during his spell at Roots Hall, preferred the higher level of Conference football.
The forward's departure is another blow to Town's hopes of finding a strike partner for the recently signed Joff Vansittart and comes hot on the heels of Barrington Belgrave's decision to opt for Farnborough Town instead of the Broadfield Stadium.
Belgrave (below), a former Norwich City forward, was released by Nationwide Division Two Southend United, but despite Reds boss Francis Vines being the first to show interest, the 22-year old, who scored 10 goals fom 62 matches during his spell at Roots Hall, preferred the higher level of Conference football.