I have a theory as to why management doesn't consider him a prospect either. To me, it seems like there are 4 different groups in pre-season.
Group A: Play 1 or 2 games, make the team regardless of performance. They're locks. Guys like Kreider, Zibanejad, Panarin, Trouba, Staal etc.
Group B: Fringe players and prospects who play 3 or more games to give coaching staff an extensive look at what they have. Kravtsov, Andersson, Chytil, Fox.
Group C: Players who won't make the team but still earn a game or two in pre-season. Reunanen, Jones, Robertson, Keane, Fogarty come to mind.
Group D: Fillers, to make sure they have enough warm bodies in practice. Leedahl, Gropp, Day etc.
Brett Howden played 2 pre-season games, and he made the team. Does he fall in Group A? Was he always going to make the team? It's not impossible. If so, it would also explain why he was ahead of Lias Andersson who, by all accounts, performed better. Beat writers said so, fans share the opinion. It's not just me saying this.