BOSTON -- Call it the Marcus Smart paradox.

The Boston Celtics' backup guard is among the NBA's worst shooters this season -- connecting on just 31.2 percent of shots overall -- and yet the team's offense is decidedly better when he's on the floor. The more shots that Smart misses in a game, the more Boston's win probability seems to grow.

Consider this: When Smart shoots 30 percent or worse from the field in a game this season, the Celtics are 11-0. When he shoots better than 30 percent, Boston is a mere 5-4.

While more pronounced this season, this does not appear to be happenstance. Smart's career winning percentage in games he shoots sub-30 percent is .641. That winning percentage drops to .598 in games he shoots better than 30 percent.

Observers find it difficult to offer an explanation other than this: On nights that Smart struggles with his shot, he tries so hard to impact the game in other ways that it more than offsets his shooting woes.

An example: When the Golden State Warriors visited earlier this month, Smart finished the game 0-for-7 shooting with one point. Yet he made countless impact plays on the defensive end and was integral to Boston twice rallying from double-digit deficits to win.

Smart contributed seven rebounds, three assists, two steals and -- most importantly -- his defense helped Boston emerge with a 92-88 triumph that extended -- and validated -- the Celtics' double-digit win streak. Smart finished plus 15 in 31 minutes.

"[Smart is] a guy that figures out ways to win," said Celtics coach Brad Stevens, who can't take Smart off the floor during crunch time. "Sometimes you can look at that conventionally and other times not. There's a reason he's in the game when the game is on the line. And there's also a reason why, [in recent narrow victories over Golden State and Toronto], the [big rebound] ended up in his hands. He just has a knack for making those types of plays."

Smart's field goal percentage has actually climbed nearly 5 percent over the past two games as he has gotten hot from the field. That's an absurd leap at the quarter mark of the season for a high-volume shooter.

Fresh off scoring 15 points on 7-of-8 shooting versus Indiana on Saturday night, Smart registered season highs with eight field goals (on 13 attempts) and 23 points against Detroit on Monday night. The Celtics rallied to win against the Pacers but lost to the Pistons.

Among the 353 players averaging at least 10 minutes per game, Smart ranks 340th in the NBA in field goal percentage.

Despite his shooting struggles, Smart ranks seventh in the NBA in traditional plus-minus at plus-156 for the season. He's one spot ahead of Golden State's Kevin Durant (plus-145). The Celtics do not win 16 straight games nor do they own the best record in basketball at 18-4 without Smart's efforts.

Stevens has leaned hard on Smart this season. Despite coming off the bench -- a spot Stevens has preferred Smart in for recent seasons in order to allow him to run the second-team offense -- Smart is fourth on the team in minutes at 30.8 per game.

Given his shooting woes, you'd expect Smart to be a liability to Boston's already inconsistent offense. Just the opposite, the Celtics own an offensive rating of 107.1 in Smart's 615 minutes of floor time, or 2.6 points higher than Boston's season average. The Celtics' offensive rating plummets to 100.7 when Smart is on the bench.

More noticeably, Boston's net rating with Smart on the court is plus-11.2 points per 100 possessions. That drops to minus-0.8 when he sits. Only Al Horford has a better net differential (plus-13.3) than Smart this season.

Brad Stevens knows Marcus Smart's impact goes beyond the box score: "He just has a knack for making those types of plays." Greg M. Cooper-USA TODAY Sports

There's no denying Smart's offensive struggles. He is averaging a mere 0.722 points per play this season, according to Synergy Sports data, and he ranks in the ninth percentile among all NBA players. Narrow that list to those with at least 150 finished possessions and Smart ranks 176th out of 180 qualified players (a list that finds Los Angeles Lakers rookie Lonzo Ball at the very bottom).

Smart ranks fourth on the Celtics averaging 10.1 shots per game. He's getting up more shots per game than Horford (9.9). Because Smart rarely reels himself in on poor shooting nights, some view him as an unapologetic chucker who doesn't have the self-awareness to throttle back. But Smart is very much aware of his shooting woes. The fact that he's thinking about his misses might actually be contributing to his struggles.

According to NBA shot data, Smart is shooting 40.9 percent overall and 57.1 percent on 3-point attempts during shots in the final four seconds of the shot clock. It hints that he's capable of being a more consistent shooter when he doesn't overthink things.

Despite the poor numbers, teammates want Smart to continue to fire away when he has quality looks. That includes Horford, who pulled Smart aside after Friday's win over the Magic and encouraged him to simply calm down.

"All I said was for him to make sure he stays the course and makes sure he keeps doing what he does every day, working on his shooting, and all that work is gonna pay off," said Horford. "And not to get discouraged. It's hard, it's easier said than done. But he's stayed with it and stayed professional and we see the results."

Smart shot the ball so well in Monday's game against the Pistons that Detroit coach Stan Van Gundy compared him to Cleveland marksman Kyle Korver. Horford's pep talk might have been just what the (shot) doctor ordered.