He usually struggles in big games and what I mean by "big" is the very most important, toughest games. Like the 5-6 biggest games of the year. For me that was rivalry games, ncaa tournament games, late rounds of the conference tournament, and games against the very best teams (especially on the road).
Other than that, he is a very good player. Maybe now that he is a senior he will have gotten even more mentally tough and will take the next step where he will be strong even in those games.
And for those that struggle with nuance, this does not mean I hate Knell. It does not mean that I don't think he is a good player. It does not mean that I am rooting for him to fail. It does not mean that I do not think he should get minutes. It does not mean that he never plays well in big games. It just means that generally, in the biggest games, he has played poorly. That is all it means.