By Brian Robb, CBS

BOSTON — A mere month ago, Marcus Smart had the best shooting month of his three-year NBA career. His 45 percent accuracy from the field in February is not an impressive feat for most NBA players, but it served as a sign of progress for the 35 percent career shooter. The 6-foot-4 hybrid guard has always been known for being a defense first player, but he was also starting to keep teams more honest himself on the offensive end.

In March however, that growth has come to more than just a steady halt. Instead, Smart has regressed to a new offensive low, hitting a mere 29.1 percent of his shots from the field while averaging 10.1 attempts per game. His shooting touch has been even worse from the perimeter where he’s hitting a putrid 18.3 percent of his 3-point shots while hoisting up four shots per game. Overall, it’s the worst shooting month of Smart’s career and his play has been a major factor in Boston’s slippage in offensive rating since the All-Star break.

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Despite the accuracy woes, Smart still is taking more shots (10.1) than his season average (9.6) during March, which has led to some fans questioning his shot selection. It’s an issue that Brad Stevens has not been afraid to discuss with the guard.

“We talk about what kind of shots people take as a team,” Stevens said before Friday’s game against the Magic. “But one of the things we really stress is creating opportunities playing inside out, but then stepping up confidently and shooting when we go inside out. Those shots – you know, if a guy goes through a stretch of games where he’s missing inside out plays, then that’s just part of it. We missed some inside out plays the other night.”

Smart is far from the only guard struggling with his shot this month. Fellow backcourt mate Terry Rozier is in his own slump, hitting just 29 percent of his shots from the field in March as well. Still, while Rozier’s minutes have been on the decline lately, Stevens is as reliant as ever on Smart (28.1 per game) for major minutes, causing Boston’s offensive rating to dip 10 points below its usual average to 97.8 points/100 possessions with Smart in the game.

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That type of drop off is concerning for a team that is floundering whenever All-Star Isaiah Thomas is not on the floor already. He’s easily the worst high volume 3-point shooter in the league, averaging 28.9 percent of his career from downtown. Despite those woes, Stevens is keeping faith in his reserve point guard, particularly in late-game situations.

“I know this about Marcus and you know it too – he’ll make big ones,” Stevens said. “I believe in him shooting when it comes to him, and obviously he’ll have to make the right decisions.”

The public vote of confidence should come as a welcome sign for Smart, but if the Celtics want to make any noise in the Eastern Conference this postseason, they need much more efficiency out of their 23-year-old guard on the offensive end.

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Brian Robb covers the Celtics for CBS Boston and contributes to, among other media outlets. You can follow him on Twitter @CelticsHub.