4. Sebastian Aho - 1 year, $825k AAV
The only reason this contract isn't higher on this list is because it's only one more year. After that, he'll be an unrestricted free agent, and if the Islanders plan to re-sign him, they'll have to give him a well-deserved raise. But purely for next year, this might be the best value contract on the team.
For a while, Sebastian Aho was the seventh defenseman who'd be healthy-scratched upwards of 50 times per season. He had potential, but the flashes of offensive talent didn't make up for the inconsistency and poor defensive-zone play.
Then, all of a sudden, he became a very strong two-way defenseman who was not just adequate, but actively good, at defense. He scored 23 points last season, which isn't particularly many, but stood strong in his own end. While he was on the ice, the Islanders gave up 28 shots per 60 minutes (second-fewest among Isles' defensemen, behind only Pelech) and 2.41 expected goals per 60 (fewest on the Islanders).
He's not an elite shutdown defenseman like Pelech is. But he became a dependable two-way guy, used more regularly as the year went on, and for only $825k, it's a very team-friendly deal.