2 year bridge is what I expect... if he's not traded before.
what I'd love to see, is the 6 years <5M$. he's not a risk to "cash in" and shut it down. At worst, he's a slightly overpaid for 2-3 years, and then a reasonably priced middle-6 C through the last 1/2 of the deal.
Likely... a bit overpaid for 1-2 years, then a bargain/value quality 2nd line C for 4-5 years, especially with the cap going up through that timeframe.
best case, a bit overpaid for 1-2 years, then breaks out into a high quality top-6C, eventually a legit top-line C, on an absolute steal of a cap hit through the last few seasons... the kind that would allow a competent GM to build a monster roster around him (& suzuki/caufield/romanov/ghule et et).
we gambled a few years ago, poorly, on Drouin. and got burnt.
we gambled in the other direction, with the forced bridge, on PK. and got burnt.
I hope at some point we have a GM who does a good job of talent identification and picks the right horse to gamble on... I think JKO, coming off of the season he did, is exactly that horse.