He missed 3 games due to the mumps. The reality is that he created zero separation between himself and the rest of the pack, which for the most part, is what has happened throughout most of his career. Check out his stats before the mumps. Tied in points in the same number of games as Seguin who had 21 goals to his 9. A handful of players right behind them. No separation whatsoever 1/3 of the way in.
The guy missed a few games because of the mumps and may have felt some lingering effects for about a week after coming back (speculation or just another excuse why he underperformed?). The talent that he and the fantasy that others see him as, should have had him winning that Art Ross missing at least 10 games. He was 27 years old going against some of the weakest competition ever and he underwhelmed.
The mumps. Every excuse in the book always trotted out. What a farce.