Beginning his career in the Liverpool youth system, Whittle spent twelve years at Anfield before moving to Dunfermline Athletic in 2012, making fifty-eight appearances.
He had a brief spell with AFC Fylde before joining Southport in March 2016, making seven appearances.
After leaving Southport, Whittle signed for York City where he played fifty-nine times.
Whittle has been struggling with a niggling hamstring injury picked up shortly after joining Forest Green in January which has seen him restricted to just two substitute appearances and a start in the Checkatrade Trophy defeat to Yeovil Town.
As a result, he has been sent to the Merseyrail Community Stadium in a bid to gain valuable match time with a view to being back with Forest Green for the last few games of the campaign.