J.R. Smith’s Defense Is Upside Down The Cavs’ swingman is often really good at defending star scorers but struggles with the second fiddles.

CLEVELAND — It was about this time two years ago when Cavaliers guard J.R. Smith graced us with a quote that summed up his career better than any other.

“I’d rather take a contested shot than an open shot any day. … It’s kind of boring when you take open shots,” Smith told ESPN’s Cavs reporter Dave McMenamin after hitting eight 3s — most of which were guarded closely — in a Game 1 road victory versus the Atlanta Hawks during the Eastern Conference finals.

Perhaps what makes his comment so fitting is the fact that its basic premise — that Smith thrives in harder scenarios and struggles with ones that most people would find to be easier — also seems to apply to the 31-year-old’s defense. This postseason, Smith has been fantastic when he has been responsible for guarding the opposing team’s star scorer. In round one, he shut down Indiana’s Paul George. And in the conference semifinals, he stifled Toronto’s DeMar DeRozan. But when he has been tasked with defending a lesser opponent — the team’s second or third scoring option — he has struggled.

AGAINST SMITH AGAINST OTHER CAVS ROUND PLAYER TEAM PLAYS PTS/ PLAY FG% PLAYS PTS/ PLAY FG% Quarterfinals George IND 32 0.91 34.6% 61 0.97 38.2% Semifinals DeRozan TOR 29 0.86 28.5 46 1.07 50.0 Conf. Finals Bradley BOS 18 1.06 41.1 33 0.85 40.0 How players fare when J.R. Smith is guarding them this postseason Paul George, DeMar DeRozan and Avery Bradley are the players Smith has guarded most this postseason. The numbers only include half-court possessions on which Smith was the primary defender. Source: ESPN Stats & Information Group

This dynamic culminated on Sunday night, when Smith failed to cover Avery Bradley during Game 3’s pivotal moment. During the game’s waning seconds, Smith got his wires crossed with teammate Iman Shumpert as they both followed a cutting Jae Crowder into the paint. This caused Smith to lose track of Bradley, who sprang free for a wide-open, game-winning 3.

Celtics coach Brad Stevens deserves credit for drawing up a play that pressured the Cavs’ defense at the rim. He also deserves credit for choosing that play with Smith on the court, given his defensive shortcomings.

At 6 feet 6 inches, Smith is a prototypical size for an NBA swingman. As he showed in the first two rounds time and again, he’s still agile enough to stay in front of all-star caliber scorers.

But if and when Smith is defending off-ball, it’s a greater challenge for him. Sometimes it’s a matter of Smith’s identifying whether he should be switching a defensive assignment, as was the case with Shumpert on Sunday. In other instances, he pays a bit too much attention to the ballhandler and loses sight of his man, who finds daylight behind him, or beyond the arc, for a score.

Teams also know they can neutralize Smith’s defensive ability, on or off the ball, by setting screens on Smith, as he struggles to navigate around picks on that end. (Smith, who developed a reputation for running into screeners, doesn’t make great use of his peripheral vision and ran into the screener 54 percent of the time in pick-and-roll scenarios this season, the NBA’s second-highest rate among guards, according to Synergy Sports.)

Offenses have exploited Smith’s weaknesses on defense for years. They’ve even been exploited by Bradley before. These two examples happened on back-to-back plays when Smith was on the Knicks and responsible for guarding Bradley during the first round of the 2013 playoffs.

The problem resurfaced in the the following round against Indiana that postseason. In the waning minutes of a close, series-ending Game 6, Smith lost track of George and then Lance Stephenson twice in a 75-second span.

Some of Smith’s issues here undoubtedly stem from focus, especially when things like this happen on consecutive plays in a postseason setting. Either way, these lapses can’t be simply chalked up to Smith’s being a poor defender, because he thrives with tougher assignments.

Last postseason, for instance, Smith did a better job statistically holding DeRozan, Kyle Korver and Klay Thompson in check than he did Detroit’s Kentavious Caldwell-Pope, who shot 45 percent and scored an efficient 1.20 points per play against him during a first-round series, according to numbers from ESPN Stats & Information Group. The year before that, Atlanta’s Kent Bazemore managed to shoot better, and score more efficiently, against Smith in that postseason than Thompson or Chicago’s Jimmy Butler.

In some cases, Smith appears to allow different amounts of space between him and the man he’s guarding, depending on how big a threat he perceives them to be from one play to the next. On average, he was within 3.4 feet of DeRozan’s shot attempts and within four feet of George’s attempts, both distances that would qualify as “tight” defense, according to STATS SportVu’s camera-tracking system. But Smith has been giving Bradley closer to five feet of space for his shots, which would qualify as an “open” shot. That’s a risky strategy, given that Bradley is tied for having made the most uncontested 3-pointers this postseason, hitting 43 percent of those shots going into Tuesday’s Game 4.

Smith’s ability to defend capably, whether he’s on or off the ball, figures to be huge in the upcoming finals, assuming the Cavaliers do indeed go on to beat Boston. Smith almost certainly won’t guard Stephen Curry and likely won’t be a regular on Kevin Durant, so he’ll be forced to defend Thompson. Smith has had some some success guarding Thompson in the past, and the All-Star has also been struggling mightily this postseason. But given how Thompson moves without the ball, and the unusual way Golden State frees up its shooters with creative screens, many of Smith’s weaknesses could be called into question.

Whatever the case, one thing should be clear: J.R. Smith can defend. It just might require him to guard a star in order for you to see it.