Last July, the Boston Celtics looked like the class of the Eastern Conference and the biggest threat to challenge the Golden State Warriors for the throne. Fast forward a year later, and things are, well, different.

Not only are the Warriors afterthoughts in the ever-changing NBA landscape, but the Celtics have gone from Eastern Conference favorites to somewhere in between where they were in the 2016-17 and 2017-18 campaigns.

They certainly have a higher ceiling than they had in 2016-17, but they may not be as good as they were in the latter year.

Gone is Kyrie Irving, a move which seemed inevitable once the Celtics were bounced from the second round of the playoffs in May. But what came out of left field was Al Horford landing a $100 million deal from the Philadelphia 76ers.

It was widely assumed that Horford, who had a $30 million player option for next year, would decline his option and then sign back with Boston on a two or three-year deal at less annual money, but instead, the 33-year-old received a surprisingly large offer and took it.

So, the C's were not only down Irving, which was somewhat expected, but they were also sans Horford, who was their best player the last three years and meant everything to them on both ends of the floor.

Another rather staggering move occurred in Beantown following Horford's decision to play elsewhere, with the C's signing Kemba Walker to a four-year contract.

Going from Irving to Walker is an outstanding pivot, as Walker is the next best thing and is certainly better in the locker room. But Horford is almost irreplaceable, which, coupled with the fact that the trade of Aron Baynes and the free-agent departures of Marcus Morris and Terry Rozier seriously compromises the Celtics' depth, is why Boston's offseason has to be seen as a loss overall.

To be fair, the C's have done a solid job otherwise. Walker was a huge move, and picking up Enes Kanter on what is essentially a one-year, $5 million deal is a massive bargain. The Celtics also brought Daniel Theis back on the cheap, and draft picks Romeo Langford and Grant Williams certainly have some potential, particularly in the case of Langford.

This also isn't a matter of Boston wanting to change things; its hand was forced, and you can absolutely understand the C's not wanting to give four years and $100 million to an aging Horford.

The good news for the Celtics is that with Kawhi Leonard's decision to head to the Los Angeles Clippers, the East has been weakened overall, as there really is no standout team at the moment. The Indiana Pacers seem to be the most well-rounded, and the Horford-Joel Embiid frontcourt in Philadelphia is definitely eye-opening, but both teams lack depth, and the 76ers' roster overall is an odd fit.

So, even with all of the winds of change sweeping through Boston this summer, the C's could still very well be one of the top teams in the East, and a 50-win season coupled with a trip to the conference finals would not be all that surprising. After all, they did that in 2017 with what a less talented roster overall.

Remember: the Celtics still have Gordon Hayward, and with a full year of recovery under his belt, he could be in for a big season next year, and a duo of Walker and Hayward certainly sounds good. You also have to expect that Jayson Tatum and Jaylen Brown will be better with more freedom, and we know what Marcus Smart will give the team.

Essentially, Boston has done everything it could this offseason to remain relevant, but it's still a tough pill to swallow.