Trading a star core player from a contending team is not usually a popular move with a team’s fan base, but we’ve seen two such moves this season improve a pair of Western Conference contenders. The Oklahoma City Thunder have actually benefited from dealing James Harden to Houston, and the Memphis Grizzlies are 16-6 since trading forward Rudy Gay to Toronto in a three-team, six-player deal on Jan. 30, the latest victory coming on Marc Gasol’s tip-in at the end of