Trade-protection clauses once reserved for only the NHL’s elite players have become ubiquitous leaguewide. A whopping 320 players this season have some type of no-trade clause (NTC) in their contract, according to PuckPedia and a recent story in The Athletic. That’s an average of 10 per team. And because players aren’t eligible for NTCs until they become an unrestricted free agent — or in the years of an extension that extend the date they would…