He wanted to keep the NCAA route open. You sign, you're automatically ineligible for the NCAA. We're gonna keep having this conversations in the months & years to come about CHLers who get drafted.
Ex: Jake O'Brien (Brantford Bulldogs, OHL) is drafted this summer by the Boston Bruins, an organization that loves the NCAA route for developing prospects. The Bruins could strongly encourage/steer O'Brien to local programs like Boston University, Boston College, Providence, UMass, Northeastern, or national powers such as Michigan, Michigan State, North Dakota, Denver and spend a year or two there & develop better before entering pro. O'Brien could say "no" and want to sign, and then the Bruins would be faced with a difficult question about whether to cave & sign him or hold strong and push him to the NCAA.