I would definitely wait this one out until August 15. There are too many unknowns.
Hockey's Future website- " His junior season ended abruptly with a thigh injury that necessitated several surgeries, but Hayes is expected to be healthy and ready for his senior season at Boston College."
http://www.hockeysfuture.com/prospects/kevin_hayes/
That statement alone tells me that he still has allot to prove at the next level. Sure, he performed well this past year after the surgery, but that's playing 40 games at the Collage Hockey level. Can he do it at the AHL or an 82 game NHL season and if he can for how long? Suffering a season-ending quadricep injury that required surgery needs to be taken into account when we could draft a similar type player that is healthy, with a high second round pick.