Joe Mazzulla doesn’t wear guilt lightly. And even now, one year after the championship win and validation as head coach, he admits there’s one moment that still lingers like a missed box-out in crunch time. “The hardest part about coaching that first year was when we didn’t win,” he said. “I was like, man, I let Al [Horford] down.” Not Tatum. Not Brown. Al.

That’s how deep the roots run with Boston’s quiet cornerstone. For Mazzulla, coaching Horford wasn’t just about the basics of the game. It was about management. A responsibility. “You take on the journey of each of your guys,” he explained. And with Horford nearing the final chapters of a quietly epic career, Mazzulla carried the weight of time.

“We didn’t give Al what he deserved. That was something we had to carry into the next season.” And boy, did they deliver. Banner 18 belongs to Boston. But for Al Horford, it feels like more than a career bookmark and might just be the mic drop he needed all along. Because in Mazzulla’s eyes, Horford wasn’t just a steadying force.

He was the blueprint. “Jayson [Tatum] does it kind of the way Al did it,” Joe Mazzulla said, explaining how the veteran’s influence shaped the Celtics’ culture. “You need each guy’s way to be able to set the tone and the temperature.” And well, it’s not hard to see why.

Horford averaged 12.9 points, 7.9 rebounds, 3.2 assists, and shot nearly 37.7% from three in his entire career so far. But his impact went far beyond the stat sheet. He was the vet in the room. The adult in the huddle. The one who reminded Jaylen Brown and Jayson Tatum how to navigate not just games, but expectations. Still, despite Mazzulla’s admiration and despite his integral role, the writing might be on the parquet.

Is Horford done with Mazzulla’s Celtics?

Asked about Horford’s future, Celtics GM Brad Stevens didn’t sugarcoat it either. “We made offers to both Luke [Kornet] and Al. We would’ve loved to have both of them back. I’d say that’s unlikely,” he said. Gulp. And just like that, retirement rumors gained steam.

“I could probably talk about Al my whole press conference and not say enough,” Stevens added. “But I don’t want to speak in absolute terms until an ultimate decision is made.” Translation? Al Horford is likely gone. Either headed to a rocking chair or, possibly, a different jersey… though that second option would break Boston’s basketball brain.

Because if anyone has defined this Boston Celtics era beyond Tatum and Brown, it’s Al Horford. Stevens said it himself: “A winner, and did everything he could for this organization… [He] impacted our younger players, who now have to take what they’ve learned from the Jrues and the Als and apply that.” Al was never the loudest. But his example echoed. So what’s next?

If this is goodbye, it comes not with a scandal or a press conference, but with two back-to-back confessions. One from his coach, who feels he owed him more. One from his GM, who knows he’s irreplaceable. It’s fitting, really. Horford always let others do the talking. And yet, it is now crystal clear that whether he laces them up again or not, Al Horford didn’t just play for Boston. He set the damn standard. And in Joe Mazzulla’s book? That standard won the war, even if it cost him a little sleep.