Question: Michael G. Barnett, is a Canadian ice hockey executive currently serving as Senior Advisor to the President-General Manager of the New York Rangers, Barnett negotiated the playing and marketing contracts for which Canadian retired professional hockey player, who played in the National Hockey League from 1983 until 2000, and was able to play both the forward and defense positions?
Sentence (from "Mike Barnett (ice hockey)"): He is best known in the world of hockey as a former agent representing sports icon Wayne Gretzky for two decades.
Relevant evidence: No