Brook Lopez

Andrew Wiggins went from being a sort of bleh wing defender who was just tall and athletic to an elite stopper who anchored the perimeter defense of a championship team

KAT going from a liability to being a plus defender really catalyzed the Knicks Title run this past year

Grant Hill wasn’t poor in his prime but he became quite a more focused defender especially matchup assignment wise when he went to Phoenix in his mid 30s

He even got DPOY votes but weirdly no AD team spot

Fred VanVleet went from being hunted on defense every time he was on the floor to guarding Steph Curry in the NBA Finals.

jr smith. sometimes players just need a lesser role on offense alongside being in a winning environment to start getting credit for their defense, and you can see the potential by their measurements from the get go.

Probably not “extremely good”, but Steph became a more solid defender and good in team defense once he got stronger

I remember the late Cliff Robinson being mainly a scorer and then turning absolute menace by end of his career. Similarly, Ron Harper post injury

Klay Thompson

Weird saying it was as he aged because he was only 25, but Andrew Wiggins was a really bad defender early in his career, and improved a lot once he got to Golden State. He always had a lot of the tools for it, and was able to turn a corner once he got there. 

Tony Allen, considered one of the best defenders ever, initially came into the league as a scorer. He realized he couldn’t make it in the league as an offensive threat and pivoted his focus to defense.

For me it has always been Paul Pierce; going from a high volume offensive player early in his career to epic man on man duals with prime LeBron James.

Jaylen Brown jumped on every pump fake his first couple of years. Improved steadily his whole career..

While not “extremely good” a current player that comes to mind is Steph

For awhile he was someone who was a defensive liability then eventually became a serviceable defender.

Billups

LeBron was pretty damn bad early in his career. 07-08 was the turning point after his first finals loss, then 08-09 he was a beast.

JJ Redick

Was viewed as a defensive liability when he came into the NBA.

But turned it around when he guarded Ray Allen in the playoffs. From there on, his defense improved, especially his team defense.

Jason Kidd comes to mind

Steph peaked on defense at 34 in 2022, 14 years into his career, very wild

Vince Carter was an underrated defender once he stopped being a star and became a role player.

Dan Majerle

Rip Hamilton

Kerry Kittles

Chris Weber

Manu Ginobili

Trevor Ariza

Bobby Jackson

Kinda opposite of this. But I remember reading how Michael Redd was not really a shooter in college and had very average numbers. But after getting to the league and being on a team with Ray Allen he worked to get better at it and basically his NBA career is known being a great 3 point shooter

I think people miss the most obvious. Curry.

When Jackson coached the team, Curry – a bad defender – was someone they had to hide on that end. Obviously he was soo good offensively, it was worth it. When Kerr took over, he told Curry that they weren’t going to keep hiding him. He had to pull his own weight.

I wouldn’t say he’s a great defender now, but he’s relatively solid on that end of the floor.

Most of the other examples, as dudes who always had the knack (could always do it for short stretches), but didn’t try. Curry, was just bad. He’s not prime Kawhi now, but he’ll make a stop if you just come at him. He’s often still their worst defender, but that’s more to do with the fact that they often surround him with great defender who can pass and/or shoot (e.g. Klay, Draymond, GP2 etc)

kevin love for one possession

Landry Shamet

Jr Smith was an underrated defender for the Cavs. Not all defense level or anything, but he was good.

Brook Lopez was pretty bad in Brooklyn when he was a primary offense option before becoming one of the best defenders in the league in his mid 30s in Milwaukee.

Richard Jefferson was inconsistent but athletic defender in his Nets day. Became a valuable 3 and D guy for Cleveland.

Antonio McDyess is someone who reinvented his game to be a defensive bruiser after several injuries.

Recent entries here (since the Knicks are NBA champs) are KAT and Clarkson.

KAT has improved his vision, not only in passes/assists but also in defense, which helps with his discipline. He still has some streak of silly fouls but not too egregious - as evident in how he handled Wemby as Exhibit A.

Clarkson on the other hand - wow! If he did not step up with his occasional steals, offensive rebounding and hustle plays, dude should’ve been out of the league already. His previous mold of inefficient small-bodied combo guard is getting out of fashion, good thing he reinvented himself, and he became champion as a result, along with his 6MOY as his career resumé. He should be a case study in how to prolong a career.

KAT would look lost and couldn’t defend the pnr if his life depended on it. He wasn’t a good rim protector either.

In the playoffs he hit a switch. He became a great defender. I love that man

The shamgod is another one who became a really pesky defender.

Jordan clarkson stepped up big time and his hustle was really noticeable.

Brook Lopez for sure

Wiggins is probably the first guy that comes to mind for me.

In Minnesota he had all the tools but was pretty inconsistent defensively and honestly looked disengaged a lot of the time. Then he gets to Golden State and suddenly he’s guarding the other team’s best wing every night and was huge defensively during that 2022 title run.

Brook Lopez is another good one. He wasn’t always terrible, but he went from looking like a slow offensive center that the league was passing by to a legit DPOY-level rim protector.

Steph also deserves a mention. He was definitely targeted earlier in his career, but over time he got stronger, smarter with positioning, and became a perfectly solid defender in Golden State’s system.

My list would probably be:

Wiggins,Brook Lopez, JR Smith, Steph Maybe LeBron if we’re talking about biggest improvement, although he was never really a bad defender to begin with.

Landry Shamet was an important wing defender these last two seasons with the Knicks, and I don’t remember his defense at all when he was with Sixers, Clippers, or Nets.

To a lesser extent, Jordan Clarkson was all hustle in the Finals run, which was so fun to watch.

I know Kornet looked awful in these last playoffs, but his defense with Boston was very good. He wasn’t a great rim protector early in his career, but he was one of the best defensive centers off the bench with the Celtics.

There are also offensive stars who take up the role player mantle late in their career. Blake Griffin’s offensive progression from the Clippers to the Pistons is impressive, but he was an awesome hustle player with the Nets and Celtics. LMA was kind of similar for the Nets. Andre Drummond has got better at pretty much everything as his role has gotten smaller and more defined, including defense. As many others have mentioned, this also applies to Brook Lopez, whose offensive role shrunk after leaving the Nets, but he became a great rim protector

Player development can completely change a career with the right coaching and effort. Defense is one of the skills that often improves with experience and better positioning. It’s always impressive to see players reinvent themselves on that end of the floor.

Bill Laimbeer. Drafted by Cavs but unsigned, so played a season in Italy. 2nd and 3rd seasons couldn’t crack starting rotation. Traded to Detroit and became their defensive anchor until retirement. 

James Harden. The only way was up j/k

Has anyone said Chris Bosh yet? Known as a sieve in Toronto, he anchored some all time defenses in Miami. Not only did he become a better rim protector, he could switch out on to the perimeter as well.

We might as well call this the “Mike Brown” award because half of these guys mentioned went to a Mike Brown coached team and suddenly became good.

Steph Curry

Michael Jordan, Kevin Durant.

Maybe it’s not purely coaching, but “oh shit, I can’t do this one thing as well anymore, maybe I should provide value in another way so I have a job”, more in the case of older guys in the league awhile.

I swear no one remembers this, but people weren’t talking up Draymond Green’s defense when he was drafted. He was probably a better scorer than defender in college.

Im reading these names in the comments and none of these guys were “bad” and then turned “good”. They all had the capabilities and showed tendencies. 

Most of this is just high usage = low effort/energy on defense -> new team and less usage = much better defensively

Nick Young for 1 season after playing beach volleyball over the summer.

Biased take but Brunson was supposed to the reason we could never win.. undersized guard never really known for defense but despite physical disadvantages his hustle and willingness to take charges helped hom contribute in other ways

Shout out KAT too.. another supposed liability really “locked up” Wemby as much as one can and proved a lot of doubters wrong..

Having OG, Mitch and bridges helps not gonna lie but critics were calling mikal washed on that end too

Hakeem, he started off as a basketball player LOL now defensive GOAT

Ben Simmons