Over the summer, the Boston Celtics lost two of their main guys in Kyrie Irving and Al Horford. These two All-Star caliber players entered free agency this offseason, and both decided that their time in Boston was up. Irving made his way to the Brooklyn Nets to form a new dynamic duo with Kevin Durant, while Horford took his talents to the Philadelphia 76ers, who are now looking like one of the heavy favorites to come out of the East this coming campaign.

The Celtics suffered two huge blows this summer — not to mention the departure of Terry Rozier as well — but the addition of former Charlotte Hornets cornerstone superstar Kemba Walker meant that the Celtics will remain relevant in the Eastern Conference.

As a matter of fact, some experts are even picking the C's to be one of the dark horses to secure a top 3 seed in the East. Today, we take this one step further and look at some factors that might just propel Boston to becomming a legitimate title contender in the 2019-20 season.

Kemba the Talisman

Walker, who joined the Celtics via a sign-and-trade deal that sent Rozier to Charlotte, comes in as virtually a like-for-like replacement for Kyrie Irving. On paper, Kyrie is a better player than Kemba, with the former not only having the statistical advantage to lay his claim, but more importantly, with an NBA title under his belt. Nevertheless, a lot of factors need to be taken into consideration in determining whether or not Walker is capable of filling the void left by Kyrie.

For one, fit is going to be extremely important. Will Kemba be a better fit with the current Celtics lineup as compared to Irving? It's impossible to tell at this point. However, what we do know is that during his time in Charlotte, Walker was a true professional. He spent the first eight years of his career with the Hornets, always remaining loyal despite the team's stature. This is exactly why the people of Charlotte still have so much love for Walker despite his decision to walk out the door this summer.

This type of professionalism and blue collar mentality is exactly what the Celtics need right now, and coupled with his proven leadership, Kemba might just be able to take Boston to heights that Kyrie Irving never reached during his brief two-season spell with the C's.

A Year of Breakouts

For the Celtics to be a serious threat in the East, a lot will be asked from their young guns. To be more specific, the spotlight will be shining brightly on incoming third-year small forward Jayson Tatum and 22-year-old guard/forward Jaylen Brown. With Irving and Horford now out of the picture, these two studs will have more room to operate in head coach Brad Stevens' system, and surely, how they perform in the upcoming season will have a huge impact on the Celtics as a whole.

After a breakout rookie campaign, Tatum further elevated his game as a sophomore last season. However, some might argue that the leap was not as huge as most would have expected. The former third overall pick averaged 15.7 points (on 45.0 percent shooting), 6.0 rebounds, 2.1 assists, 1.1 steals, and 0.7 blocks, while also connecting on 1.5 three-pointers per contest on a 37.3-percent clip. These numbers are not bad at all, but Tatum will need to take the next step this season if he hopes to establish himself as the team's unquestioned number two option on offense behind Walker.

The same can pretty much be said about Brown, whose numbers dipped slightly in his third year in the league last season. The former University of California standout will need to trend in the opposite direction this coming campaign, as Boston will need for him to step up as the team's x-factor this term.

Under the Radar

Who can forget Boston's memorable run in the playoffs a couple of years ago? This was when Irving and Gordon Hayward were down and out, but a banged up Celtics side somehow mustered the strength to star in what was easily the best Cinderella story of that season.

This year, Boston will once again have the underdog label entering the new campaign. All eyes in the East will be on the likes of the Sixers and the Milwaukee Bucks, allowing the Celtics to operate relatively under the radar. This is perhaps where a team like Boston will thrive the most, and if all goes according to plan, they might just emerge as the surprise package of what should be an extremely competitive 2019-20 season.

In truth, the Celtics' chances of winning the championship this coming season are not very optimistic. There are a lot of other teams that will be fielding more formidable lineups — on paper, at least — and with their current roster, the odds are definitely stacked against the Celtics. Nevertheless, the fighting spirit and competitiveness remains as strong as ever in Boston, so who knows, we might just be in for quite a surprise.