Leeds United took on Queens Park Rangers in their most recent development match.
Leeds's development squad took on Queens Park Rangers in their most recent outing, and picked up a 3-3 draw.
The likes of Souleymane Doukara, Lee Erwin and Casper Sloth all played in the contest, and Hart believes they have staked their claim for a spot in Rosler's starting line-up.
"I don't think they have done themselves any harm [with their performances]," he said. "They have shown the manager that they are intent on making a challenge and I think the first-team coaching staff will be delighted with that.
"The senior players that came down set a great example to the kids."
Erwin and Doukara were Leeds' two goalscorers in the fixture against QPR, and their showings will have caught the eye.
Erwin scored twice from two instinctive finishes from close-range, and showed the talent which made the Whites bring him to Elland Road over the summer.
Doukara, meanwhile, lashed home a brilliant volley, which should have strengthened his claim for further opportunities this season.
Doukara has made just four appearances under Rosler so far, but he will be hoping his good form for the under-21 proves that still has a part to play.