What’s going on with Jae Crowder?

For the first two years of his NBA career, Jae Crowder didn’t make much of an impact. As an edge-of-the-rotation guy on a few decent Mavericks teams, he was perhaps better than the average second-round pick, but not by much. Then he arrived in Boston, and everything changed.

When the Celtics acquired Crowder from the Mavericks in the Rajon Rondo trade, it hardly seemed like a big deal. Hey, the Celtics had to get something for their four-time All-Star point guard, right? However, Crowder blossomed as a member of the Celtics, becoming a key player on a team that would eventually become the top seed in the Eastern Conference.

In Boston, Crowder gradually evolved into a quality 3-and-D guy, putting up modest usage rates and quietly being effective on both sides of the ball. He gradually got better and better from downtown, going from 28.2 percent in his first season with the Celtics to 39.8 percent last season. Crowder was never going to a lead a team in scoring, but he gained a reputation as the type of player who does everything right. As such, when the Cavaliers acquired him as part of the trade that sent Kyrie Irving to the Celtics, it seemed like quite a pick-up for them. Between Crowder and Isaiah Thomas, it felt like perhaps the Cavaliers had gotten the better of the Celtics.

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Now, though, we’re a month into the season, and while Thomas is still recovering from a hip injury that will sideline him until at least January, Crowder looks like a much worse version of the player we saw in Boston.

In 14 games with the Cavaliers, Crowder’s numbers are down across the board. He’s shooting 38.0 percent from the field and 31.6 percent from 3. Could he rest on his strong defense? Not exactly. His Defensive Box Plus-Minus is -2.3, an alarming development considering that number has been positive in every other season of his career (although, to be fair, his individual mark is likely heavily influenced by the Cavs horrific team defense). Crowder has gone from being extremely reliable on both sides of the ball to possibly being a net negative on both.

One possibility is that we’re witnessing another iteration of The Stevens Effect. Since Brad Stevens took over the Celtics in 2013-14, there’s been a trend of players thriving under him but flailing elsewhere. First, there was Jordan Crawford, who won Eastern Conference Player of the week honors in December 2013. He played his best basketball under Stevens, but flailed after being traded to the Warriors mid-season. His minutes per game was slashed in half, and he would be out of the league for the following two seasons. Then, there was Evan Turner, who played so well as a sixth-man under Stevens that the Blazers offered him a four-year, $70 million contract. Turner’s production in Portland has failed to match what he did in Boston, and the Blazers are likely experiencing some buyer’s remorse.

Crowder has a better reputation than Crawford or Turner, but it’s still worth noting that Stevens has a great ability of getting the best out of players, and that could explain his plummeting production.

What likely isn’t helping matters is that the Cavaliers are just a bit of a mess right now. They’ve held on to a .500 record thanks to the superhuman play of LeBron James, but they’ve looked like a bad team that happens to have one amazing player. When considering the decline in Crowder’s defense, it’s worth remembering who he’s been sharing the floor with. In Boston, there may have been the poor defense of Thomas, but he was also flanked by stout defenders like Marcus Smart and Avery Bradley. In Cleveland, he’s playing with the likes of Derrick Rose, J.R. Smith and Kyle Korver, all of whom have been terrible defenders this season. (Rose in particular has an horrific Defensive Box Plus-Minus of -4.6).

The aspect of Crowder’s game that’s most likely to improve as the season goes on is his shooting. It’s a small sample size, and when you share the floor with shooters like Korver, the opportunities are going to come. But his inability to stand out on defense seem like a greater problem. In Boston, he benefited from a great system. In Cleveland, he’s stuck in a disorganized situation that doesn’t know how to use him.

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How much of Crowder’s struggles are his own fault, and how much of it is a result of the chaos around him remains to be seen, or a statistical quirk that makes it look worse than it is. If Tyronn Lue can unlock the same quality basketball player than Stevens had in Boston, Crowder could still be a key piece as the Cavaliers look to make their fourth straight NBA Finals. If not, what looked like a key piece of the Irving trade could end up being a mere afterthought.