Defender Jack Hobbs was dismissed as the last man but Rovers failed to take advantage as Rickie Lambert had his effort saved, and the team failed to find a leveller.
Trollope said: "You have to give Leicester credit. They are not top of the table by accident and are tremendous defensively.
"It's not often Rickie Lambert has let us down this season and he has apologised to the lads for missing the penalty.
"But I'm equally concerned that, although we huffed and puffed, we needed better decisions on the ball. We weren't positive enough and when players had one-on-one opportunities they tended to play safe."