18 shamrocks: Reflecting on Al Horford's unique legacy in Boston

18 shamrocks: Reflecting on Al Horford's unique legacy in Boston originally appeared on NBC Sports BostonEighteen shamrocks.That’s how we’ll always remember Al Horford’s time in Boston. Nine years ago, that was how he declared his intention to join the Celtics on social media. It was both a celebration and a promise. For the first real time in team history, a big-time free agent was choosing to come to Boston and, with him came true hope of raising the franchise’s next ba