Marcus Smart could be the Celtics' X factor

WALTHAM, Mass. -- It seems unfair to suggest that, after an offseason in which the Boston Celtics handed out the richest free-agent contract in team history, the player most important to their overall success might be a reserve guard on a rookie deal.

But if the Celtics truly intend to take a leap forward this season and emerge as a legitimate contender to the Cleveland Cavaliers in the Eastern Conference, third-year point guard Marcus Smart might be as important as his All-Star-caliber teammates Isaiah Thomas and newcomer Al Horford.

This notion is not lost on Smart, who is aware of the buzz he has generated. But in his jovial and relaxed Texas-boy demeanor, Smart, 22, shrugged off the suggestion that those sorts of expectations might weigh on him.

"I feel it, but I don't feel it as pressure," he said. "It's a challenge. And, as an athlete, this is what you live for."

In two seasons with the Celtics, Smart, the No. 6 pick in the 2014 draft, has established himself as a future All-Defense stalwart with the sort of versatility that allows coach Brad Stevens to throw him on the likes of Paul Millsap and Kristaps Porzingis when those big men were torching the Celtics last season. Smart, who is 6-foot-4, plays at full tilt and routinely makes Vine-worthy hustle plays that have endeared him to Boston's fan base.

Smart is most certainly still learning how to be an NBA point guard -- though Celtics brass often commend his strides since last season -- and he has a propensity to embellish contact, if for no other reason than a relentless desire to draw a whistle that might aid his team. And, yes, Smart is well aware of his shooting struggles.

Smart shot 34.8 percent from the floor last season, including a cringeworthy 25.3 percent beyond the 3-point arc. Good luck finding a metric that sugarcoats those difficulties from the perimeter. Smart had one of the worst 3-point shooting seasons in league history, even though he had some stretches -- including a now-famous post-Snow Day performance -- in which he seemingly channeled Steph Curry.

Smart is the first to acknowledge his shooting woes. Asked what he has been working on in the offseason, he said at Monday's media day, "My decision-making, coming off ball screens, working to get into the lane and finishing and, as everybody knows, still working on my jump shot and becoming a more consistent shooter."

After last season, Smart huddled with the Celtics' player development staff and the video team to analyze his shooting struggles. He came away with some hints that he believes will help him find more consistency beyond the arc.

"I tried to take as much of the hitch out of my shot as possible," Smart said. "I tried to get a quicker release. And just work on repetition. My dip was too far below my waist, therefore it was taking me a longer time to get my shot up and making it easy for a defender to contest me. [Defenders] ultimately made me change my shot a lot."

If Smart evolves into just an average 3-point shooter, it's going to open things up for him. He doesn't have to become an elite scorer, because his defensive talents and intangibles already separate him from most players his age.

Smart is one of the bodies that will compete to fill the void left by Evan Turner's departure. The Celtics often leaned on Turner as their second-unit ball-handler, which forced Smart to play off the ball much of last season, and Turner emerged as a Sixth Man of the Year candidate. It's fair to wonder if Smart is the same sort of player who needs the ball in his hands to thrive.

Computer projections are particularly bullish on Smart this season. FiveThirtyEight's CARMELO projection model sees Smart more than doubling his wins above replacement player from last season (2.5). What's more, the CARMELO projection labels Smart as a future All-Star with a five-year market value of $156.5 million.

Nagged by a hodgepodge of maladies over his first two seasons, Smart is at full strength entering training camp and eager to showcase his improvements. He spent part of his summer in Las Vegas with USA Basketball's Select Team, scrimmaging against the national squad that won gold in Rio.

Now Smart wants to show what he learned.

"I'm excited. Really excited," Smart said of the upcoming season. "I’m healthy, so that's a good thing. It's my third year, and my teammates have a lot of confidence in me. The [coaching] staff, too. I have a lot of confidence in myself at this point."