Vrby was a 4th liner for ¾'s of the year because of his piss poor attitude, so yes you are right he played with Radim on the 4th line.
He was ready but you are asking a skilled forward to play on your 4th line with Dorsett and for a large chunk of the year Prust. That's like asking a climber to climb Mount Everest with only a thermos and a Columbia jacket. Sorry but McCann never saw enough time for anyone to say he was garbage or didn't show signs of life. The same people who say he didn't show much promise are the same people who judge a players career by a 20 games stint.