Six years ain't bad considering he turned 27 in November, and 5m is pretty manageable. 43 points in 15-16 with 19 goals and a 30ish point guy since. They're probably banking on him being more a consistent 40 point guy. It's hard to say though, with the Isles defense first approach his production may suffer.
Four or five years would have been better, but that's hockey.