The Challengers: Ranking the four biggest threats to Celtics in East

The Challengers: Ranking the four biggest threats to Celtics in East originally appeared on NBC Sports Boston

Want to find out how the Boston Celtics stack up against the best teams in the Eastern Conference? You won't have to wait long.

The Celtics play 13 of their first 15 games against East opponents, and that includes a 2023 Eastern Conference Finals rematch against the Miami Heat this Friday at TD Garden, two road matchups with the Philadelphia 76ers in a span of seven days in early November and a showdown with Giannis Antetokounmpo, Damian Lillard and the new-look Milwaukee Bucks on the Wednesday before Thanksgiving.

Of course, that assumes the Heat, Sixers and Bucks will be among Boston's chief competitors in 2023-24, which is no guarantee. The upstart Cleveland Cavaliers and gritty New York Knicks will be eager to break into the top tier of East contenders this season, especially in light of the current drama in Philly (more on that later).

So, who should Celtics fans keep their eye on as the biggest threats to Boston in the East? Here are four teams (and an honorable mention) to watch.

Milwaukee Bucks

2022-23 finish: 58-24, No. 1 seed in East, lost in first round to Miami Heat

Key offseason additions: Damian Lillard, Malik Beasley

Key offseason departures: Jrue Holiday, Grayson Allen, Jevon Carter, Wesley Matthews

The Bucks collapsed in crunch time during their shocking first-round playoff loss to the Heat, averaging just 22.0 points per game in the fourth quarter. Enter Lillard, one of the best clutch scorers in the NBA.

Lillard gives the Bucks' offense a massive boost, and the Lillard-Antetokounmpo pick-and-roll combo should be lethal. But Milwaukee lost a massive defensive presence in Holiday, who's now on the rival Celtics. The question will be whether Lillard can hold his own defensively in a seven-game playoff series, and whether Khris Middleton can stay healthy enough to be make legitimate contributions on both ends.

Some believe the Holiday-Lillard swap would favor the Celtics in a postseason matchup, but we shouldn't underestimate a hungry and motivated Bucks squad that's by far Boston's toughest competition in the conference.

Cleveland Cavaliers

2022-23 finish: 51-31, No. 4 seed in East, lost in first round to New York Knicks

Key offseason additions: Georges Niang, Max Strus, Tristan Thompson

Key offseason departures: Cedi Osman, Danny Green, Robin Lopez

The pieces are all there in Cleveland. Donovan Mitchell thrived in his first season with the Cavs and forms a potent guard duo with Darius Garland. Jarrett Allen and Evan Mobley are an elite defensive frontcourt pairing, and Strus gives the Cavs much-needed shooting at the wing.

Cleveland's lack of experience was exposed last postseason, however, and the team also needs more out of Mobley in Year 3 if it wants to be considered a legitimate title contender.

The Cavs have enough talent to land the No. 3 seed in the East and gave the Celtics fits last season, taking three of the teams' four matchups. Until they prove themselves in April and May, however, they'll remain second fiddle to Boston and Milwaukee in the East.

Philadelphia 76ers

2022-23 finish: 54-28, No. 3 seed in East, lost in second round to Celtics

Key offseason additions: Patrick Beverley, Kelly Oubre, Danny Green

Key offseason departures: Jalen McDaniels, Montrezl Harrell, Shake Milton, Georges Niang

No team in the East has a greater gap between their ceiling and floor than the Sixers. Why? Two words: James Harden.

Harden continues to be a major distraction in Philly, where he finally reported for duty Wednesday after a lengthy hiatus but won't play in the team's season opener. Harden seems determined to force a trade, leading to speculation that big man Joel Embiid could jump ship as well.

If Embiid and Harden are both on the roster, this team can win 50-plus games and threaten the Celtics for East supremacy, especially with former Coach of the Year Nick Nurse at the helm.

That's a massive "if," however, and if the Harden saga continues much longer, things could go south in a hurry.

Miami Heat

2022-23 finish: 44-38, No. 7 seed in East, lost in NBA Finals to Denver Nuggets

Key offseason additions: Thomas Bryant, Josh Richardson, Jaime Jaquez Jr. (rookie)

Key offseason departures: Gabe Vincent, Max Strus, Victor Oladipo

On paper, the Heat shouldn't be here. They finished seventh in the East last season, lost two key contributors this summer in Vincent and Strus and whiffed in the Damian Lillard sweepstakes. But we just can't count out a team coached by Erik Spoelstra and led by Jimmy Butler that came within three victories of an NBA title in June.

Spoelsta will have to earn his paycheck this season, leaning on aggressive defense and hoping that Tyler Herro can be a consistent third star behind Butler and Bam Adebayo. What's more likely is that Miami gets outsized contributions from undrafted role players and meets Boston in the East Finals for the third consecutive year.

Honorable mention: New York Knicks

Are we overlooking the Knicks, who won 20 of their final 30 games last season and sent the Cavs packing in five games of Round 1?

New York's trio of Jalen Brunson, Julius Randle and R.J. Barrett should benefit from a full season together, and Tom Thibodeau's club will always rank among the NBA's best defensive squads. So, you could make the case for the Knicks over the depleted Heat or volatile Sixers here.

But the bottom line is that experience matters in May and June, and the Knicks have won just one playoff series in the last 10 years. We’ll give the edge to the teams that have gone toe-to-toe with the Celtics in seven-game playoff series as the bigger threats to Boston’s East supremacy.