The Millers, who Evans took charge of a fortnight ago, are unlikely to make the play-offs this season, sitting five points adrift of seventh-placed Crewe with two games to go.
But the 49-year-old will work his players hard in a bit to create the right mentality.
"You set a mentality where everything is winning," he said. "At Crawley if we drew it was a crisis. If you have got a winning mentality then you have a nasty streak.
"We have an intensity at which we work at. The players are fit, I would be demeaning if I said they weren't, but they're not fit enough. Some of them.
"I know it's the back end of the season, but the boys are going to come in and work."