The Tynecastle club sit at the bottom of the table 18 points adrift from safety, with only 33 points available to play for from the remaining 11 games - starting with a match at Motherwell on Saturday.
Locke admits that, behind the scenes, the club are preparing for life in the Scottish Championship, but states that as manager of the team he would not be doing his job if he wrote off their chances of top-flight survival.
"We need to be realistic, we'll have to win seven or eight games," Locke said. "It's certainly a tall order but the opportunity is there. I think we're playing well enough, the results of late have showed that.
"All we can focus on is the next game. We know it's going to be tough - Motherwell are having an unbelievable season - but if we can go there and get a win then we're looking to Kilmarnock the next again week. That's as far as we are looking.
"We'd be foolish not to be preparing for the negative eventuality, but there are people at the club who are there to do that.
"I'm paid to work on the football side of the club and that's what I try to do to the best of my ability every day."