Mike Koster, a Minnesota native who enjoyed a successful career with the University of Minnesota after being drafted by the Maple Leafs in the 5th round is a right-handed shooting defenseman, something the team desperately needs a surplus in. While a bit undersized for a defenseman, he has the playmaking prowess to be a third pairing defender that can stabilize the back end in the future.
Much like Miettinen, Koster has until August 15th to sign his deal before the Maple Leafs lose the rights; and with someone who has experience playing with Matthew Knies he could find that chemistry again and be a solid piece for the Maple Leafs in the future.