BOSTON -- If the Boston Celtics had been fully healthy, Jaylen Brown likely would have viewed the final minute of Sunday night's game from the sideline. He would have watched while five of his teammates tried to steal victory from the Detroit Pistons. He might have cheered or waved a towel. He could have sprinted off the bench to celebrate a big Celtics play or slunk backwards in response to a Pistons dagger.

Instead, Brown stood in the right corner, waited for a pass from Al Horford, and proceeded to drill a go-ahead 3-pointer with a foul. Bad luck has forced the Celtics to deal with one critical injury after another this season, but the fallback from that has allowed Brown to see increased opportunities throughout his rookie season. He has started 15 games now, including one against LeBron James on national television. He has played shooting guard, small forward and power forward, and even defended some point guards. He has shown an advanced post game for his age, 20, and a soft touch from the corners. He has flown for alley-oops, guarded some of his the world's best scorers (to various levels of success), and, yes, lost his man too many times.

The last point coaxed a laugh from Avery Bradley. Since the preseason, Bradley has steadily praised his youngest teammate, calling Brown a "very special player" who will prove his doubter's wrong. But the Celtics also treat Brown like a younger brother. They make fun of him. They don't always respect his calls in 1-on-1 games after practice. After Brown's huge shot against the Pistons, Isaiah Thomas and Amir Johnson went on Instagram to do this:

So after noting Brown's impressive defensive development, Bradley smirked when asked exactly how the rookie has progressed.

"Umm, staying on his guy," Bradley laughed.

He continued: "He's honestly improved. We still make jokes about him every now and then and he still messes up. It's just a desire to want to learn every single day, play as hard as he can. I respect him for that and, like I said, he's been playing very well."

"I think he's been improving every single game, not only him but Marcus (Smart), James Young, all those guys have been taking advantage of the opportunity they've been given. I'm happy for him. Jaylen's been playing very good on the defensive end. That was something that he struggled with at the beginning of the year, as you guys all know, it's all about opportunity and learning the game and having confidence and that's what he's playing with right now. He's playing very well."

The frustrating part about rookies -- even the best ones -- is how quickly they can shift from promising to incompetent. Brown can look like a future All-Star one possession while spinning for a fast-break bucket, but has yet to harness all of his physical ability. Even when he strings together a couple of wow moments -- and he delivers a lot of them -- the next reminder of his inconsistency is only moments away.

The Celtics should still be pleased with their choice at No. 3. Since Bradley suffered a setback to his strained Achilles on Jan. 16, Brown -- thrust into the starting lineup for 12 games -- has averaged 14.5 points and 6.7 rebounds per 36 minutes while shooting 45.0 percent from the field, including 37.8 percent from behind the arc. During that span, he has shown flashes of the dynamic scorer he might become, earning free throw attempts at a better rate than any other Boston player with the exception of Isaiah Thomas. With Brown filling in as a starter over the last month, the Celtics went 10-2.

For the season, Brown ranks in the 94.3 percentile league-wide with 1.14 points per possession in the low post, according to NBA.com. While the sample size there is small, he has punished guards near the rim, with the footwork, strength and athleticism to cause plenty of mismatches down there. Especially if his shooting stroke continues to progress, it's not hard to envision Brown becoming a matchup nightmare, capable of bursting past slower defenders or bruising smaller ones.

For now, it's just nice to see him improving. Not many rookies learn how to contribute to a winning team.

"In a lot of ways Jaylen has made strides," Celtics head coach Brad Stevens said recently. "And he still has strides to make in a lot of ways. But we're excited about the way Jaylen has progressed the last couple of months."