Wednesday’s latest clutch 3-pointer by Jaylen Brown serves as a reminder. Somehow, some way, Brown regularly manages to surprise Boston Celtics fans — and even more journalists and critics.

Just weeks ago, one news blogger posted the latest in what was a click-bait regular all season — the dreaded “Jayson vs. Jaylen” survey. Just yesterday, NBC noted with some surprise that Brown has been “pretty good” as the Celtics won 9 of 10 with him in the lineup since the break.

(Hmmm… today on NBC, 9 months ago on Celtics247. Last summer we wrote: “Jaylen Brown and the 10-game stretch that turned around the Celtics season.” Brown’s development was quite evident even then during a similar 9-of-10 skein.)

So it may be time to review where Brown is — and how he’s developed. To anyone who’s been (ahem) paying attention, none of this is should be surprising at all.

Brown’s steady development

The 21-year-old’s improvement is evident in virtually all phases of the game.

Brown the defender

When he volunteered to play in the summer league last May, Brown paid a visit to Danny Ainge. “I’m ready,” he said “– now.” Ainge reportedly loved that visit — especially Brown’s responding with alacrity when Ainge told Brown he’d probably be asked to be the team’s primary defender against top opposing guards and many forwards.

Mission assigned? Mission accomplished. From signature individual plays like a critical steal against Utah to a timely contest against DeMar DeRozan in a 1-point Celtic win, Brown delivered. He out-performed the likes of Klay Thompson in two matchups against the world champion Warriors that the Celtics split. He held his own as the Celtics went 10-6 against the top 8 teams in the West, teams including guys like Jimmy Butler, Russell Westbrook, James Harden, and (most recently) Donovan Mitchell.

(Given the Celtics system and ubiquitous switching, this is not to say that Brown spends the entire game matched up against these players. But he often does. And this is exactly what Ainge and Brad Stevens intended.)

Among players with more than 40 games and 25 minutes per, Brown (100.0) is the 5th-rated defender at any position in the NBA. He ranks second among guards, trailing only Marcus Smart (99.4).

You prefer defensive win shares? Among the same group, Brown is 4th in the league at any position — tied with Smart for first among guards at 0.56.

Why Brown is not a lock for at least second-team all-defense is beyond us. Of course, this tends to be a reputation award built up over time. And one that relies heavily on counting stats, like steals. If you go by the advanced stats that Analytics Guy is always touting, though, Brown is right there. He’s ready — now.

Brown on offense

Shooting

Brown’s development as a shooter this year has surprised many. But if you looked closely at the numbers, it was already underway in 2017.

For the entire 2016-17 season, Brown shot 45 percent from the floor, and 34 percent from 3-point range, for a true-shooting percent of 54 percent. All were improvements over his freshman year at Cal, and all pretty credible for a 20-year old rookie.

But in games in which Brown started (20 games), his true-shooting rate rose to 57 percent. In games in which he played 20 minutes or more (27 games), 58 percent. In games after the all-star break (25 games), 59 percent (rounding up from 58.5.), with a rate from 3-point range of 38 percent. During one NBA season, Brown took perhaps the weakest part of his game and developed to an above-average NBA performer.

This year? Even better. For 2017-2018 as a whole, Brown’s true-shooting rose to 56 percent from 54 percent last season, so far. His effective field-goal percentage, .508 last season, .531 this season.

If you’re paying close attention, you may notice that these numbers aren’t that far from his situational rates at the end of 2017. But this view overlooks Brown’s somewhat increased role this year — as well as in-season improvement. In January and February (17 games), Brown’s true-shooting rate rose to .581. Since the all-star break (10 games), Brown’s true-shooting percentage has climbed to .613. His ORtg rose every month this year except January, from 98 in October to 109 in February and March.

For the season as a whole, Brown’s development, as we’ve noted, places him on a rough par with both Butler and Thompson in their sophomore campaigns. And at a younger age.

Brown’s free-throw shooting became a problem in December, when he converted a Lonzo Ball -esque 51 percent. Brown reportedly spent time with Kyrie Irving during the team’s London-week break, and hit the gym. Whatever he did seems to have helped. Brown converted 68 percent of his charities in January, 75 in February, and (so far) 90 percent in March.

Clutch shooting

Pop quiz time: Can you name the top two clutch-time and and clutch-squared-time shooters on the Boston Celtics? That would be Brown (62 percent effective field-goal rate in clutch, 100 percent in cluth-squared) and Tatum (52 percent in clutch, 75 percent in clutch-squared).

Big caveat: Naturally, Brown and Tatum have a smaller sample size than all-stars Irving and Al Horford. And they’re often shooting in more favorable situations. If you need someone to create a late-game shot, it’s likely to be Irving, often against a top opposing defender or double-team.

Still, the disparity is not as big as you might think. For the year, Brown has a combined 45 clutch- or clutch-squared attempts. Tatum, 91. This puts Brown well behind Irving (134), Terry Rozier (107), and Horford (72) in sheer attempts — but by about one-fifth to one-third an order of magnitude.

(“Clutch” shots have “an elevated impact on a game’s outcome.” Clutch-squared shots are “critical to a game’s outcome” — generally, buzzer-beaters or potential buzzer-beaters. More on the definition of clutch and clutch-squared at InPredictable.com.)

Handles, passing, finishing

Around the rim, Brown is less polished than some would hope. But, as in most phases, improving. Brown has been both stronger and more efficient around the rim, as well as creating more opportunities on his own.

Last season, Brown completed 30 dunks. This season, so far, 50. And just over half (this season) of those dunks came off an assist.

Brown’s shooting percentage from 0-3 feet ticked up slightly this season, to 63 percent from 61 percent. What’s especially noticeable, though, is the fact that he seldom settles for mid-range jumpers. 74 percent of his shot attempts are either from 3-point range, or at the rim (0-3 feet.)

Last year, Brown’s assist percentage was 7.2 percent. This year, 8.7 percent — more than 10 percent since January 1. Indeed, Brown’s assists per game nearly doubled to more than 2.2 over January-March from 1.2 in October-December.

Turnovers are bad? Agreed. Again, some improvement for Brown. Last year’s turnover rate of 12.5 percent has ticked down to 12.0 percent — and in higher leverage moments plus an increased usage percentage.

Enjoy the process

It’s been about 17 months since the open of the 2016-2017 season. Fans may cringe when he doesn’t convert this dunk, doesn’t use the glass on that shot, or “isn’t as polished as Jayson Tatum off the dribble.”

But in that time, he’s gone from a weak shooter in college to an excellent (and clutch) NBA shooter. He’s become an excellent NBA defender. He’s working on his handles and free throws.

Stop worrying, Celtics fans and pundits. Many banners will rise between now and, oh, 2036. In short: Enjoy the process.