"It is a sad day. I don't want anyone to think that this is not a gut-wrenching decision for me," Sturrock said.
"The challenges of football that have been put in place - the lure of The Premiership - are what all managers dream of.
"It has been very difficult. The timing was very disappointing, to say the least.
"I would have liked to have finished what we have started this season, but football is like that at times, it kicks you in the teeth."