If the Boston Celtics go on to win an NBA championship, Al Horford’s Game 4 performance will live in Boston sports lore until the east coast breaks off into the Atlantic Ocean, or however climate change really sinks its teeth into this planet.

Without him on Monday night, the Celtics go down 3-1 to the defending champion Milwaukee Bucks, and instead return to Boston with an even series and have retaken home court advantage. None of that is possible without Horford’s spectacular performance. Of the 30 points that he scored — a playoff career high — 16 of them came in the fourth quarter, including two monster 3-point shots, the last of which would give the Celtics a lead late in the fourth quarter that they wouldn’t relinquish for the rest of the game.

For as much as the Celtics needed all of those points last night, when Horford has been at his best for them it has been on the defensive side of the ball. Per Stat Muse, when he guards Giannis Antetokounmpo, Horford has been able to hold him to 30.6 percent from the field.

While Monday was a career night for Horford, it’s also a statistical outlier. Though a five-time NBA All-Star, nothing else stands out when looking at his basketball reference page. He’s known as a dependable scorer, but he has never even averaged even 19 points per game in a season. He has only averaged double-digit rebounds once in his career and has been named to that same number of All-NBA and All-Defensive teams. Even when he was at Florida — the last great multi-season run in men’s college basketball — he averaged less points per game than Joakim Noah and was never a consensus All-American, but Horford would be the No. 3 overall pick in the 2007 NBA draft and Noah would be selected ninth.

The scouts knew then what NBA players, media, and fans would find out later. While there is nothing spectacular about Horford’s game, his steady presence and basketball I.Q. that’s the height of Josh Smith’s vertical jump, he’s the type of player that will always make a difference for a team — unless of course he’s playing alongside Joel Embiid in the 2020 COVID version of the NBA.

Following back-to-back college national championships in 2005 and 2006 — Florida is the only men’s program to accomplish that feat since Duke won consecutive titles in 1991 and 1992 — he went to the Atlanta Hawks and made an immediate impact. Smith and Iso Joe had already been there for two seasons when Horford was drafted, but hadn’t done much to get the Hawks out of the tailspin they had been in since the turn of the millennium — no playoff appearances. Not only did the Hawks make the playoffs during Horford’s rookie year, but as an eighth seed they took the eventual NBA champion Celtics to seven games in the first round.

During Horford’s time with the Hawks, they never missed the playoffs. Sure many of those series were on NBA TV, but for the first time since Dikembe Mutombo, Mookie Blaylock, and Steve Smith were winning 50 games at The Omni and the Georgia Dome, the Hawks were a winner. Sure Josh Smith failing to be the first player to usher in the 3-point era five years early was frustrating as was Jeff Teague’s inconsistent play, but the person who held it together was Horford. In the high post, in the low post, both on offense and defense he was their rock. So what if he didn’t put up Iso Joe’s numbers? It was his offensive rebound and score that gave the Hawks the 3-2 lead against the Washington Wizards in a 2015 playoff series and would help propel the franchise to its first conference finals appearance since it was in St. Louis. Until Trae Young’s performance in last year’s playoffs, it was the undisputed biggest play in the history of the Atlanta Hawks.

That was Horford’s last season with the Hawks. He would go on to sign a contract with the Celtics, where he would completely change his game. It’s in Boston where his defense would become nationally recognized for him putting a young Embiid on punishment every time that Celtics would play the Philadelphia 76ers, and still be able to switch on the perimeter when necessary. Then on offense, he could still do what he did with the Hawks, but the Celtics needed more space in the paint for their offense to work.

So after averaging more than half a 3-point attempt per game only once while with the Hawks, Horford would not only attempt more than three per game consistently with the Celtics but in four seasons with them, he shoots them at just under 37 percent. Something he tried for one season in Atlanta, would be crucial to help the Celtics to consecutive Eastern Conference Finals appearances against LeBron James and the Cleveland Cavaliers.

After two years away in Philadelphia and Oklahoma City, the Celtics brought Horford back to their lineup with Jaylen Brown and Jayson Tatum, who were no longer college-age kids, but young NBA All-Star men. Since January, the Celtics have arguably been the best team in the league, and are in a dog fight right now with the Bucks. As great as Tatum and Brown have been since the turn of the year, who got the Celtics through a road game they trailed most of and desperately needed to win — Horford.

When his career ends, how he’s remembered will depend on where a person lives and/or how big of a basketball fan they are. Those in Atlanta and Boston will have memories of him in their happy place for the rest of their lives. For basketball fans, he will be remembered as the clear-cut best player of one of the best college basketball teams of all time, and being worthy of all the pre-draft hype. This top-three pick may not have made a great deal of viral plays, nor been a statistical monster in the NBA, but he has played excellent, winning basketball for 15 seasons, 18 if you count his time at Florida.

Since the Basketball Hall of Fame is not restricted to professional careers, he deserves serious consideration. He’s one of the faces of men’s college basketball’s last reign of dominance, and however you feel about one-and-done, that is a historic achievement. Throw that in with five NBA All-Star appearances and being a key contributor on competitive teams for the overwhelming majority of his career, that’s a resume worthy to be displayed in Springfield.

If he doesn’t get there, he’ll certainly have the respect of those who watched and worked alongside him for two decades. Horford may not have been a 20 or 10 guy, or had eye-popping advanced analytics numbers, but if you’ve watched him play since he was on standard def in Gainesville you know what you saw — consistent great play.