JALEN GREEN HEARS the wrath from the old man with the unmistakable, raspy voice.

It's a little less than an hour before the Rockets' shootaround begins, but almost half the roster is already on the Footprint Center floor in Phoenix, running three-man pick-and-roll drills.

John Lucas, the Rockets' 68-year-old assistant coach, provides running commentary throughout the workout, usually while standing on the baseline. Green, the Houston Rockets' prized rookie shooting guard drafted No. 2 overall, is Lucas' primary target. Green had just picked up his dribble near the free throw line and nonchalantly scooped a lefty lob pass when Lucas peppers his 19-year-old pupil.

"That's too f---ing sloppy!" Lucas hollers. "This ain't high school! You can't throw s--- like that!"

Lucas shuffles into the middle of the lane, hands up high like a center defending the play. He declares how easy it'd be for an opposing big man to break up that pass, adding another turnover to the rebuilding Rockets' league-leading total.

John Wall -- the maximum-salaried, All-Star point guard mothballed as the Rockets rebuild around the backcourt of No. 2 overall pick Green and 21-year-old Kevin Porter Jr. -- quietly instructs Green to penetrate to the dotted line, putting himself in position to make a read based on how the opposing center reacts. Wall joined the drills after wrapping up an hour-long workout with Lucas, part of his efforts to stay sharp in hopes that Houston finds a trade destination for him.

Seconds later, Green executes as he was told, throwing a pass that Lucas praises: "There you go!"

Welcome to today's class at "John Lucas University," as general manager Rafael Stone refers to the Rockets' developmental program for the several college-aged players on their roster. The drills vary by the day, but Lucas is always ratcheting up the intensity, putting the players in competitive situations, including full-court one-on-one contests.

Lucas' hard-nosed tactics and colorful commentary -- pushing, prodding, occasionally praising and sometimes cracking up the players -- are a constant. For the 1-9 Rockets, who host No. 1 overall pick Cade Cunningham and the Detroit Pistons tonight (7:30 p.m. ET on ESPN), the lessons are not only invaluable, they're necessary.

"I'm being told all the time, 'Coach, you can't be too hard on [Green],'" Lucas says later. "I'm talking about, 'I'm not hard enough,' because I see the potential. Everybody has a different way of loving somebody.

"My love for him is not praising his ass, but to keep a foot in it."

It's an approach that Green, one of four teenage rookies drafted by the Rockets in the first round, appreciates.

"He's an old-school coach," Green says. "A lot of s--- talking. He's real old-school, like a real OG."

LUCAS' FIRST FORAY into coaching came with the USBL's Miami Tropics in 1992, when he bought the minor league franchise and won a pair of titles in his two-season stint.

Several players on those rosters had been in Lucas' drug addiction aftercare program. He could certainly relate with those hoping for another chance in the NBA. Lucas' own 14-year career, which started when the Rockets selected him with the No. 1 overall pick in the 1976 draft, had been repeatedly derailed due to cocaine and alcohol addictions.

"I'm a dope fiend," says Lucas, who has been sober since March 14, 1986, when he was waived to end his second stint in Houston. The Rockets had ordered him to take a drug test -- it came back positive for cocaine -- after Lucas had missed practice a few days earlier after awaking on a Houston street soaked in his own urine.

Lucas has been coaching since getting his first taste of it with the Tropics, all the while overseeing the aftercare program he developed, which focuses primarily on helping NBA and NFL players. He had brief stints as the head coach for the San Antonio Spurs, Philadelphia 76ers and Cleveland Cavaliers between 1994 and 2004. He also worked to develop dozens of players before they were drafted, including high schoolers Kobe Bryant and LeBron James.

Lucas has long been a major presence in the basketball grassroots scene, running boys' and girls' workouts, clinics and tournaments. Stone's sons are among the hundreds of kids who have worked with Lucas, and Stone was so impressed that he pushed the Rockets to hire Lucas to lead their developmental program when they were putting together coach Mike D'Antoni's staff in 2016.

"He makes hard work fun," Stone says.

Lucas was a finalist in the Rockets' search to replace D'Antoni before last season, in part because he had such strong relationships with the players, including James Harden. After Houston opted to hire Stephen Silas, a first-time head coach who toiled for more than two decades as an assistant, the Rockets prioritized keeping Lucas, promoting him to lead assistant.

Lucas helps run Houston's defense, while Silas leans on his head-coaching experience with rebuilding teams in Philadelphia and Cleveland. And Lucas still runs the Rockets' developmental program, the top priority for a franchise in the early stages of a rebuild.

"He is a tireless worker," Silas says. "I mean, he is up at 8 o'clock in the morning working out a guy, then working out guys before practice, working out guys after practice and then again at night. He is dedicated, committed, and he just has that personality that everybody rallies around.

"Like nobody I've ever seen before, he can make guys do things they might not want to do and make it fun or make it important to them."

PORTER RODE THE second bus to shootaround on the morning of Houston's 123-111 loss to the Phoenix Suns, which followed the Rockets' first full day off in about a month. Lucas requires Green to participate in the early sessions on game days. They are optional for Porter, whose attendance has been sporadic.

"It's his third year, and I've got to respect that," Lucas says. "I'm waiting for him to come willingly."

It is technically Porter's third NBA season, but nothing has been conventional about the first few years of his career.

Porter was considered a high-lottery talent, but he fell to the final pick of the first round in the 2019 draft due to off-court issues, stemming from an extraordinarily difficult upbringing. Porter oozed potential as a teenage rookie for the Cavaliers, averaging 10 points per game but never playing another game for the franchise.

The Cavs opted not to have Porter participate with the team in any capacity so that he could focus on his personal issues. He was arrested after flipping his Mercedes SUV in an early-morning crash on Nov. 15, 2020, when a loaded gun and small amount of marijuana were found in the vehicle, although charges were later dismissed.

"He's definitely one of the most unique human beings on this planet. I'm grateful to know him."

Kevin Porter Jr., on Rockets assistant coach John Lucas

The Cavs parted ways with Porter after he had a shouting match with team officials a couple of months later, when he was irate his locker had been moved. The Rockets pounced on the opportunity to provide Porter a change of scenery and second chance, sending a heavily protected second-round pick to Cleveland in a trade.

"We knew he had challenges," Stone says. "That's why we were able to get him. We've never asked him to be something he's not, and we've never asked him to be perfect. What we have asked him to do is work ...

"What we've gotten from him is [to] buy in, at least thus far, that we're all on the same page and that we want the same things."

The Rockets were willing to take a risk on Porter because the 6-foot-4, 205-pound lefty reminded them of a young James Harden. And, the front office and coaching staff were confident they could provide the structure and support "Scoot" needed to realize his potential. The latter is in large part due to Lucas' guidance.

"He's been someone Scoot can rely on and will be there day-to-day and has seen everything," Stone says. "Whatever he's going through, it's not going to be more dramatic than what John lived. So I think [having Lucas] is a huge advantage for us organizationally, and we've leaned into that.

"It doesn't mean you can compile a list of 15 reclamation projects, but it does mean with special people who you think have a chance, maybe you can give them the best chance."

Houston came up with a plan for Porter to ease him back into NBA action while converting him from a wing to a point guard, beginning with sending him to the G League bubble with the Rio Grande Valley Vipers, its affiliate. After dominating that competition, Porter showed flashes of stardom in 26 games for the Rockets last season, highlighted by a 50-point, 11-assist performance in a late-season win against the Milwaukee Bucks.

Porter was good enough, averaging 16.6 points and 6.3 assists per game, to convince the Rockets that handing him the reins of the offense was in the franchise's best interest. It hasn't been a smooth transition without having Wall to share playmaking duties, as Porter's numbers have dipped significantly (12.3 points, 5.2 assists and 36.7% shooting). However, the Rockets are encouraged by Porter's drastic defensive improvement, as Stone proudly noted that Porter now ranks 35th in one metric -- FiveThirtyEight's RAPTOR on/off rating -- that ranked him 469th out of 474 players last season.

Lucas compares his approach to Porter's development to "kid gloves," saying he gauges Porter's mood before determining how hard to push him that day. Lucas worries that Porter will tune him out if he demands too much.

"The biggest thing is getting to learn and know him without smothering him," says Lucas, whose one firm rule for Porter is, "Don't ever let me catch you lying to me."

Lucas and Porter occasionally butt heads. They exchanged high-decibel expletives at each other across the gym during one practice, although Lucas softened his reply by punctuating it with, "But I love you."

"He just always is on me," Porter says. "I know that I'm in his spotlight. He really emphasizes improving myself.

"He's definitely one of the most unique human beings on this planet. I'm grateful to know him. One word: unpredictable. ...You don't know what type of things he's going to say, do, nothing.

"All you know is he's going to be a great, genuine dude when you walk in the building, and he's going to uplift a room."

MOST PLAYERS STICK to a pregame warm-up routine, taking the same shots from the same spots night after night. That's not how Lucas works with Green, making that time an on-court extension of the scouting report, having him work on the looks he's most likely to get against that specific opponent.

The payoff comes in incremental progress, moments that serve as proof Green and the other young Rockets are learning, such as his driving dunk in Houston's down-to-the-wire loss to the Lakers on Nov. 2.

The play went viral on social media, but it made Silas and Lucas proud because of something simple: the way Green slid toward the corner when Porter drove baseline, giving his teammate a target and setting himself up to attack a defender off the closeout. Green didn't move from the wing on a similar play in the season opener, resulting in Porter's pass sailing into the seats.

"Our measure of success is improvement," Silas says.

The Rockets decided that throwing their core young players in the deep end made the most sense at this stage of their rebuild, no matter how far they sink in the standings after finishing last season with the NBA's worst record (17-55).

"It's going to be a tough year for us as we get better," Lucas says.

"We're all on the same page with wanting to win and wanting to be great," Green says. "We know that's going to take time, and we're all bought in right now."

Houston is particularly steadfast in its plan to allow Green and Porter to spread their wings without fear of consequences if they make poor decisions. Rookie forward/center Alperen Sengun, the No. 16 overall pick with a high-lottery grade from the Rockets after earning the Turkish League MVP at 18 years old last season, also has similar freedom in his role as a key reserve. (Guard Josh Christopher and forward Usman Garuba, the Rockets' other teenage first-round picks, who are potential impact defenders that the team is trying to develop into quality role players, will likely get significant playing time this season in the G League, if not the NBA.)

"Coach Silas has a good demeanor -- very steady, even keel. And I'm the one that's an a--hole."

Rockets assistant coach John Lucas

There is a consensus among Rockets' leadership that it's the right approach, even though it's rough on a head coach who worked half of his life for this opportunity.

"Oh, it's hard. It's hard at times, but you know that that's the growth that needs to happen," Silas says. "You start in the dirt to get where you need to be. I was lucky to be around Luka [Doncic] and Steph [Curry] and LeBron [James] when they were rookies. Guys who are that creative, you can't stifle that creative ability.

"There are going to be some crazy turnovers and some plays you wish they wouldn't make, but that's part of the growth."

Silas stresses the importance of not sweating the game-to-game fluctuations of the young players' development. He prefers to track improvement in samples of weeks and months.

That sort of patience is required from a head coach on a young team prioritizing development over results. Silas, described by Green as "laid-back" but equipped with a "switch that can flip to getting on you," has a temperament suited for the assignment.

"Coach Silas has a good demeanor -- very steady, even keel," Lucas says, cracking a wry smile. "And I'm the one that's an a--hole."

For Lucas, it isn't a glamorous job, and the rewards are often small; Houston is one of three NBA teams, along with the Pistons and New Orleans Pelicans, with only one win so far this season.

Asked if his work is fun, Lucas paused and thought for 15 seconds.

"It's my love. It's my love," Lucas says. "I've struggled with accepting my love. It's a funny thing. Nobody likes the gift you get at Christmas unless it's the gift you wanted, but you learn to appreciate the gift in time. I got the right gift."