Were the 2023 Celtics the Most Overrated Team in Betting History?

The Boston Celtics' baffling, wild, emotional roller coaster of a season ended Monday night.

After the Celtics scratched and clawed their way out of a 3-0 deficit to force a Game 7 at home, the Miami Heat waxed them, 103-84, to advance to their second NBA Finals in four years.

It was the first time this season that Boston scored fewer than 90 points in a game. Boston shot 9-of-42 from 3-point range. It was also booed in the final game of its season on its home floor.

It was a stunning end that shouldn't be that stunning given who the Celtics were this season — particularly in the playoffs.

Who were they?

They were literally the most overrated team this season.

The Numbers

Let's start here.

The Celtics are tied with the 2018 Thunder for the most losses as a favorite in a single season (29) since at least 2003.

Boston finished with the most playoff losses as a favorite since 2008, with eight in these playoffs. The Celtics have the most losses as more than a five-point favorite in that span (7).

They're tied with last year's Celtics team for the most losses as a home favorite with six. (That team made the Finals.)

A $100 bettor would've lost $367 in these playoffs wagering on the Celtics. That was for a team that made the conference finals and a Game 7.

The only teams to have a worse net profit over a playoff run since 2005 are the Clippers in the bubble in 2020, the Warriors in 2016, who had the biggest collapse in NBA history in the Finals up 3-1, and the 2015 Hawks, who ran into the LeBron buzzsaw.

In the regular season and playoffs, Boston had the most losses as a double-digit favorite, with nine since 2013.

The Celtics lost in positions they should've won more often than any team we have data for.

Among teams with at least five losses as a favorite in the playoffs, the Celtics have the second-worst ATS margin behind last year's Suns team that got annihilated in Game 7 vs. Dallas.

In a seven-game series vs. the Sixers, the Celtics were still 6-point favorites. When they dug out of an 0-3 hole, the Celtics were a 3-point favorite vs. the Heat in Miami in Game 6 and 7.5-point favorite in Game 7.

No matter what Boston did, no matter who it lost to, the market couldn't move away from it enough.

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The Narrative

The Celtics just screwed around all season, and eventually, it cost them a Finals appearance.

We should've known earlier.

Even if we move away from losses like the ones to the Rockets and Wizards in March, the first-round series vs. Atlanta was telling. Losing once to the Hawks? Sure, that's OK. This is the NBA: Teams take one, and you can have an off night in the first round.

But instead, the Hawks took them to six games.

Then the Sixers, without Joel Embiid, took Game 1. OK, fine, they caught them off guard; it happens. But then they lost Game 4 to allow the series to go 2-2. And Game 5, at home, to allow the Sixers to take home court advantage and a 3-2 lead.

The big one, though, was Game 2 vs. the Heat. You're down 0-1; OK, you're coming off a Game 7, and those are rough spots.

But the Celtics allowed the eighth-seed Heat to take a 2-0 lead in Boston.

That was when their season ended, even with their three-game winning streak to force Game 7.

The Celtics were preseason title favorites. They were favorites all season until mid-February, when the Bucks rattled off a 16-game winning streak. Then, as soon as Miami knocked out the Bucks, the Celtics became the favorites again.

The market — by power rating, liability, whatever — was always higher on the Celtics than it should've been.

What Comes Next?

There will be a lot of discussion about Jaylen Brown and his potential max extension after his All-NBA selection.

However, league sources have kept a side eye on the Brown situation for months, even before the Kevin Durant trade rumors at the deadline, and especially after.

That's not to say it's likely Brown leaves. When a team has a chance to keep a winning formula that enabled it to make consecutive Conference Finals and three in four years — including a Finals berth — that franchise usually chooses that.

But if Brown feels like he's done in Boston, that changes the equation.

There will be questions about coaching, the frontcourt and the offensive style of play.

That last point is key. Boston became essentially a make-or-miss team. When the Celtics didn't hit a consistently high percentage of 3s, it had no alternative.

The Celtics didn't have any go-to mechanisms without a consistent pick-and-roll option to rely on.

So much of the Celtics' power rating was built early in the season when they were the best jump-shooting team in NBA history for a short stretch.

But it shouldn't surprise us that, eventually, those looks didn't fall. It's bad luck for Boston, but not so bad that it's a shock.

Boston has to pick up the pieces, but for those that bet against the Celtics, it's a great lesson to learn about how bookmakers can't escape the inertia of their power ratings and liability, which provides a key opportunity to fade those teams that the numbers just can't quit on.