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SAN ANTONIO – The daily responsibilities usually involved Stephen Curry making long 3-pointers, commanding double teams and throwing dazzling passes.

The Warriors guard cannot do any of that lately. Curry has been sidelined for nearly the past four weeks with a Grade 2 MCL sprain in his left knee. Curry has spent the past week rehabbing his knee with running and elastic band exercises. And with the Warriors clearing him Friday for modified team practices, Curry will sit out for a potentially series-clinching Game 4 of the team’s first-round series against the San Antonio Spurs on Sunday.

So in between rehab exercises, Curry has assumed a different role. He has remained what Warriors guard Quinn Cook called “the ultimate mentor” and “ultimate big brother” during his first NBA playoff stint.

“Steph’s always giving him advice,” Warriors coach Steve Kerr said. “I don’t really listen to their conversations. But it’s nice for Quinn to have that voice and that friendship with Steph. He’s been a big help.”

How has that helped?

The examples seem as plentiful as Curry’s volume of highlight reels. With Cook averaging 7.7 points on 40.9 percent shooting in 21.3 minutes through three playoff games as a backup point guard, Curry has given him feedback any time he goes to the bench. Curry has chastised Cook for passing up open shots. Curry has reminded Cook not to feel discouraged about making mistakes.

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“I’m like a sponge around him. I ask him so many questions,” Cook told The Bay Area News Group. “He tells me what he sees. We have a good rapport with each other.”

That rapport started well before the 25-year-old undrafted guard spent the 2017-18 season on a two-way contract with the Warriors and their G-League team in Santa Cruz. Curry and Cook first met when Cook was teammates with Curry’s brother, Seth, at Duke (2011-13). Stephen Curry also trained at Duke during the 2011 NBA lockout. And Cook’s mother (Janet) and Curry’s mother (Sonya) soon became close friends.

“Any time we saw each other,” Cook said, “he was always giving me confidence.”

Since Curry and Cook became teammates, though, those interactions morphed from once-a-year visits toward daily conversations. A year after Curry praised Cook about his play during a short stint in New Orleans, Curry has offered more glowing words to Cook in a Warriors uniform. Curry has frequently called Cook an “NBA player” along with frequent reminders on how to live up to that description.

“Be aggressive. Be a scorer. Be a playmaker. Do what we brought him here for,” Curry said. “He can be proud of himself and what he’s about. I try to encourage that mindset as much as I can. At the end of the day, he’s been playing amazing.”

So amazing that the Warriors signed Cook to the playoff roster to address a depleted backcourt without Curry and reserve guard Patrick McCaw (bone bruise near spine). Though Cook averaged 16.9 points on 51.8 percent shooting, 4.1 rebounds and 4.6 assists in the final 15 regular-season games, Kerr started veteran forward Andre Iguodala over Cook because of Iguodala’s experience as well as his offensive and defensive versatility.

That has given Cook time to grow into a role he will keep when Curry returns. That also has given Cook time to talk with Curry on the bench.

The Warriors have consistently praised Cook for his professionalism and work habits. Cook also remains close friends with Warriors forward Kevin Durant, who grew up with Cook near the Washington, D.C., area. Cook also asks questions to veteran guard Shaun Livingston about his playmaking, aggressiveness and treatment.

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Cook has maintained his self-confidence after having the significant responsibilities in championship games with high-profile programs in high school (DeMatha Catholic High, Oak Hill) and college (Duke). The Warriors have empowered Cook with play-calling responsibilities and have allowed him to play through his offensive and defensive mistakes.

Yet, the Cook-Curry dynamic has become unique. Curry remains the Warriors’ franchise player. As Durant also noted, “Point guards always come together.”

“They’re always talking and trying to figure out different ways to gain an advantage out there,” Durant said. “Steph is the best at that with figuring out ways to be effective. Quinn is watching at all times and watching how he runs his offense through film. But he adds his different flair to it. Steph is so good at pulling people aside and letting him know what he sees as well and small tricks he used to become a great player in this league. Small guys have to stick together.”

Cook saw how much Curry valued that role, even when he injured his left knee on March 23 against Atlanta. Though he stayed in the locker room for treatment after the injury, Curry still talked with Cook at halftime about his own game. Curry has extended that guidance into the postseason during film sessions, at dinner and through text messages. With Curry on the Warriors’ five-day trip to San Antonio, Cook also has observed with a watchful eye how Curry has stayed diligent with his rehab.

“Any time you can watch a player like Steph work and what he does on the floor, you can learn. Nothing needs to be said,” said Warriors assistant coach Bruce Fraser, who works closely with Curry. “Quinn gets that. I’m not saying it’s osmosis. But just by being around him, he’s going to learn. Anything Steph may give him, it’s valuable stuff.”

Therefore, Cook said he has spent almost every moment with Curry asking him questions as if he is an inquisitive reporter. The questions are much more specific and filled with more basketball insight, though. Beyond talking X’s and O’s, Cook has become interested about Curry’s own journey.

Though the Warriors selected Curry with the No. 7 pick in the 2009 NBA draft, he fielded initial skepticism on whether the former Davidson standout will be more than just a shooting specialist. Curry then labored through ankle injuries through his first three NBA seasons. As Curry has since won two NBA championships and two league regular-season MVP awards, Cook has admired both up close and from afar how Curry has responded to the public and private adoration.

“Obviously he’s one of the greatest ever to play. But he’s an even better teammate and even better human being,” Cook said. “Just seeing how he handles everything, he’s so humble and so down to Earth. He speaks to everybody in the organization. He has a relationship with everybody.”

Cook also has a relationship with Curry. That left the Warriors backup point guard wistful on how that has prepared him for a playoff role.

“To learn from him on a daily basis,” Cook said, “I’m just thankful for the opportunity.”

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