The Boston Celtics had a strong regular season in 2026, finishing second in the Eastern Conference. Only to then fall at the first hurdle in the post-season, losing to the 76ers - who came 7th in the regular season conference. So how has the offseason been going in Boston so far, and what are the early predictions for 2027?

Well, there are few better places to look than prediction markets. These popular platforms are offering trades on NBA markets right now, where trader sentiment changes the price, which is reflected in a probability score. In combination with old-school expert views, this quantified market opinion (priced in a more transparent manner than sportsbooks) can give a good idea as to what the collective sentiment on the Celtics is right now. 

And the consensus is middling. Despite their strong winning record last season, experts and prediction markets seem to agree the Celtics have a strong chance of doing well, but are far from favorites. 

The Early Markets Consider Boston Strong but not Top-Tier 

Prediction platform Polymarket's traders give the Celtics at 5% likely to be NBA Champs in 2027. They have a 14% chance of winning the Eastern Conference at this stage of the offseason, also according to Polymarket. Some $17 million has already been put down on the former market, even this early in the season. 

For those not aware, prediction markets are big business in the US right now. There will be tens if not hundreds of millions of dollars traded on the NBA over the season at the major markets.

For just a glimpse of how big the sector now is, consider a comparison site like Covers.com and its coverage of Polymarket sign-up offers in the list here. Customers use these sites to assess their prediction market options just as they do with sportsbooks - including sign up offers, payment methods and market depth - demonstrating just how quickly online services have grown up around the prediction market model. 

Interestingly, that 5% chance on a Celtics title win offered by prediction markets is slightly behind the sportsbooks. Across most 'books the Celtics average +1400 or 6.7% implied odds. That is a great example of how pure market opinion often diverges from those set by a combination of employed expert analysis and market money. 

Eastern Conference Win is More Likely, But Offseason Made it Harder 

In terms of positioning that 5%-7% probability of a title-winning season for the Celtics puts them in around about the top five teams going into the season. 

However, they are a solid last in that pack - and their chances have been falling due to off-season developments. The other teams as rated by Polymarket are:

• Oklahoma City Thunder (22%)
• San Antonio Spurs (21%) 
• 76ers (13%)
• New York Knicks (10%)
• Boston Celtics (5%) 

For the Eastern Conference market, only the 76ers (23%) and the Knicks (21%) are considered more likely to win the conference. 

Much of the Celtics season will depend on new arrival Paul George and key man Jayson Tatum staying healthy. Although Jaylen Brown was a shock trade to the 76ers, veteran Paul George arguably could work better slotting in next to Jayson Tatum - and if both can stay clear of injuries (a big if) the Boston team could still have a big season ahead. 

The odds and markets have also been complicated by the Philadelphia 76ers acquisitions of LeBron James and Jaylen Brown. This alone has seen them rocket up in the favorites rankings, including in the title markets where they now sit in second place. However, they are the most traded team currently - which shows that many traders are also backing the no side for the Philly team. 

Brown/George Trade Hit Market Opinion 

Interestingly, or perhaps maddeningly, for Celtics fans, the team was not long ago considered around third favorite to go all the way in 2027. Some sportsbooks had them at around +600 or a 14.3% implied probability. Far off the around 5% chance consensus at most markets a few weeks after. 

That is partly due to the strengthening of other teams in the Eastern Conference, but mostly in reaction to the Brown trade. On July 6, Jaylen Brown joined the 76ers and the Celtics got Paul George, two first-round draft picks and two second-round picks. 

Brown was recently a Finals MVP, an established All-Star and, at 29, still in his prime years. George on the other hand, is a nine-time All-Star but also 36 years old (the Celtics almost signed him in 2017) and a more defensive-minded player too. So, you can see why the market found this one as a negative for the Celtics - although the draft picks could see some returns. 

In the Conference Champs market, Polymarket traders had the Celtics as much as 30% favorites for some time, until the Brown/George trade reaction saw them lose about half of that relatively quickly.