Pavel Zacha started the year hearing his name in trade whispers as the most likely veteran core player to be shipped away if things really didn’t go well for the Black and Gold again this season.Instead, the Bruins have played better-than-expected hockey that has them sitting in a wild card playoff spot in the middle of January, and Zacha has consistently been one of Boston’s most effective players during that stretch while holding down the No. 2 center spot pretty much all season. Zacha scored the game-winner in Tuesday night’s 3-0 win over the Detroit Red Wings at TD Garden on a glove-side snipe as he was moving from the top of the faceoff circle to the slot for the scoring chance.