The Chicago Blackhawks only have 2 defensemen on expiring contracts this offseason. Slater Koekkoek is another first-round draft pick that is up for a new contract next year. Koekkoek joined the Blackhawks via a trade with the Tampa Bay Lightning in January.
Obviously, Koekkoek is not going to be a top-4 defenseman in the NHL. However, he is a reliable 7th defenseman in the NHL. Koekkoek signed a contract with the Blackhawks this offseason allowing him to compete for a roster spot moving forward.
That does not include young defensemen, like Adam Boqvist and Ian Mitchell, who will eventually have a chance in the NHL. Koekkoek is going to have to earn a contract from the Blackhawks this season.