Boston Celtics could have a future star on their hands in Marcus Smart

This summer has seen the Boston Celtics engulfed in a flurry of rumors. Whether it was their free agent recruitment attempts or the idea that teams will throw their best players in our direction in exchange for Danny Ainge's bundle of assets, the narrative has been all about acquiring a superstar that will launch the Celtics into contention.

Significant progress was made with the signing of Al Horford. Not only has he provided the Celtics with an All-Star quality big man capable of pushing this team up the Eastern Conference hierarchy, but his deal eradicates the long-held notion that star players don't want to come to Boston.

Yet it's not enough for Celtics fans, who count their accomplishments only by the number of banners hanging from the rafters. Horford is a great addition that should help this team win a playoff series or two for the first time in the Brad Stevens era, but they still need that third star to join Horford and Isaiah Thomas.

Lost in the whirlwind of rumors that the Celtics are chasing an established superstar is that we may already have the star we seek on the roster already. Boston may find that a breakout season from third-year guard Marcus Smart could give them their missing piece without surrendering their most valuable assets.

Some may scoff at the idea of Smart making that leap, but some brilliant minds at FiveThirtyEight seem to believe in him. Their recently released CARMELO projections peg Smart as a future All-Star with a value that puts him in the same territory as some of the trade targets fans have been salivating over.

In case you're wondering, CARMELO is in no way a comparison to Carmelo Anthony, which is probably a good thing. Have you seen the Knicks play in recent years? No, this system developed by FiveThirtyEight estimates a player's career arc to forecast their future. According to their model, the future is bright for Smart.

CARMELO predicts that Smart will jump from 2.5 Wins Above Replacement last season to 5.1 WAR in 2016-17. That would give him the league's fifth-highest increase in WAR, while the expectation is that he'll continue to trend upwards from there. Their projection model expects him to peak at 5.8 WAR in the 2018-19 season.

To put that in perspective, Thomas led the Celtics with 7.3 WAR last season, followed by Jae Crowder at 6.1 WAR. CARMELO expects both of them to take a step back this season, in part due to the insertion of another All-Star in the mix in Horford, who produced 8.9 WAR for the Atlanta Hawks last year. Boston's deep roster and system that emphasizes ball movement and team basketball seems to deflate the value of individual players in these projections. For this upcoming season, Horford's 5.7 WAR is expected to lead the team, followed by Smart.

Fans may be clamoring for a big-name star like Blake Griffin, but CARMELO warns against cashing in their chips for the Clippers forward. According to their projections, Griffin's 5.9 WAR isn't significantly higher than what they expect from Smart, while Griffin is expected to decline further from there, with Smart surpassing his value within two seasons.

Can we realistically expect Smart to become the team's second most valuable player? It may not be as far-fetched as you think. He already does a lot of things very well on the court. He's a fierce perimeter defender, he hustles, and he's aggressive on the boards for his position. Unfortunately, his one major weakness is also his most noticeable—shooting.

Smart has shown flashes of improvement with his shooting, but he has never managed to remain consistent. His season ended with a miserable 34.8 percent shooting from the field and a cringe-worthy 25.3 percent from beyond the arc. That needs to improve if he's ever going to reach these lofty projections, and he knows it.

"My shooting," answered Smart when questioned about what he's working on this summer, per ESPN's Chris Forsberg. "Everybody knows it. I know it. I've been working really hard on it."

He has a lot of work to do in order to get his shooting to an acceptable level, but Smart wouldn't be the only star that couldn't shoot early in their careers. Remember when teams said Kawhi Leonard couldn't shoot coming out of college? Now he's one of the most accurate players in the league from three-point range and has blossomed into a superstar. NBA players can improve with hard work and dedication, and  Smart has a motor that won't allow him to stop until he gets better.

Injuries have hindered Smart's development through his first two seasons, but he's healthy now and ready to take the next step in his career. Big things have been expected from him since the Celtics selected him with the No. 6 overall pick in the 2014 draft, and this may be the year he finally lives up to those expectations.