BIRMINGHAM, Ala. — Saylor Poffenbarger had to go to Barnes & Noble recently and needed someone to go with her. She knew just who to call: her teammate Mir McLean.

“She would go with me. She loves to read,” Poffenbarger said of her friend, laughing. “I’m more into self-help books. She reads for fun.”

When Maryland’s women’s basketball team is facing an opponent armed with a talented scorer, no matter her size, coach Brenda Frese knows who to give the assignment to: McLean, a 5-foot-11 wing from Baltimore.

“She’s so versatile. We can put her on a point guard, a wing, a center — it doesn’t matter. You give her a job, she’s going to take it to heart,” Frese said. “Just that selflessness, unsung hero type of play that comes from Mir.”

Whether it’s helping a friend peruse a bookstore or being assigned to stifle an opposing player, McLean brings reliability, consistency and a strong work ethic to every task. A product of Roland Park Country School, McLean has transferred twice and missed an entire season due to a knee injury during her college career.

But now she’s in the Sweet 16 for the first time.

If fourth-seeded Maryland is successful Friday in pulling off a historic upset of No. 1 South Carolina in Legacy Arena, McLean will likely be a big reason. The graduate student and former McDonald’s All-American doesn’t start for the Terps and doesn’t lead them in scoring or rebounding, but she is often tasked with guarding the other team’s best player.

Soft-spoken and a self-described introvert, McLean can often be overlooked for her defense. But her teammates realize her importance and so does Freese.

“To see her having her most impactful minutes right now during the NCAA tournament, she’s been our most complete lockdown player on the opponent’s best player. It’s a credit to her,” Frese said. “Those are the stories you love to be able to tell of the players that just continue behind the scenes.”

After a stretch in early February when McLean played five minutes or less in four straight games — a span in which the Terps went 2-2 — Frese worked her into the rotation more. The Terps have since won six of their last seven games, a surge in which McLean is averaging 23 minutes per game.

This season, Maryland is 16-3 when McLean plays 14 minutes or more.

“Mir is someone that, when she puts her mind to something, she can do it,” Poffenbarger said. “She comes in and she’s super intense, she’s super athletic, and she gives their best player a really hard time. In big games, she plays well.”

On Thursday in the bowels of the arena, as reporters flooded into Maryland’s undersize locker room, McLean was quietly nestled in a folding chair. As her teammates had microphones pushed in front of them, cameras focused on them and lights shining on them, the kid from Baltimore who holds a bachelor’s degree in Middle Eastern language and literature from the University of Virginia was focused on the pages in front of her.

She sat with her legs crossed, with a tattered book in her right hand resting on her left knee. McLean was a few pages into Colleen Hoover’s 2015 novel, “November 9.” It’s the 10th of many books she will read this year, most of which will probably be mysteries or thrillers.

“I’ve just always been around books and school like that,” McLean says. “And entering a different world is fun.”

When McLean doesn’t have her nose in a book, you can probably find her doing a different kind of studying.

Indeed, there’s the kind that comes with classwork. McLean, the daughter of a school principal, is working on a master’s degree in international relations. She hopes to use her degrees to help refugees assimilate to America.

But there’s also the studying that McLean does in basketball.

When the Terps shift their focus toward their next opponent, McLean dives into the film. She specifically watches for tendencies and habits, and how best she can keep her opponent in front of her.

“I’m from Baltimore,” McLean says. “So just guarding and defending is something that we — Baltimore people — take care of. And just the fact that my family and friends are personally in those seats at Maryland is something that drives me.”

McLean wasn’t always known as a defensive stopper. As a high school prospect — tabbed as a five-star recruit by ESPN and ranked 25th in her class — she was heralded for her expansive skills on offense, her propensity to finish in traffic and get to the rim whenever she wanted to, and her ability to create her own shot.

But being the Terrapins’ defensive anchor gives her purpose.

“It’s been a blessing just to have that kind of responsibility, and it helps with my pride, I guess,” McLean said. “Just putting Maryland on my back and allowing me to get stops. … Every time that I get the opportunity, I’m just super excited to tackle it.”

That’s because those opportunities didn’t always exist for McLean. As a freshman at UConn, she played just 7.1 minutes per game.

Poffenbarger was on that 2020-21 squad for the Huskies, too. The two Marylanders played against each other in high school only once, but they struck up a friendship while playing for Geno Auriemma.

“We’re very similar,” Poffenbarger said. “It’s a very low-maintenance friendship.”

When the next season began, Poffenbarger and McLean went their separate ways but stayed in touch. They both transferred out of UConn — Poffenbarger finding a new home at Arkansas, while McLean landed at Virginia. Poffenbarger became an All-Southeastern Conference talent and was one of the nation’s leading rebounders last season.

McLean’s time at Virginia started well. She scored in double figures in eight of the first 11 games she played in and had a pair of double-doubles. She had five more double-doubles for Virginia as a junior in the 2022-23 campaign as the Cavaliers went on an 11-game win streak. Then, just after the turn of the new year, the knee injury happened.

“The initial injury was a dislocation of the entire knee,” McLean says. “So I tore my ACL, my MCL, both meniscal roots, and I had a cartilage procedure.”

As she sat in front of her locker, McLean’s right leg was covered in a wrap from her upper thigh to her ankle. It was a reminder of where she’s been, what she’s gone through and why she’s cherishing every second with the Terps.

“It’s refreshing,” McLean said. “I’m really proud of myself. The ups and downs have kept me at a good balance level. Never too high, never too low.”

Poffenbarger and McLean reunited this season at Maryland, two of seven transfers Frese brought in to revamp a team that lost in the first round of the NCAA tournament last year.

Those additions have helped Maryland improve on defense. From last season to this one, the Terps went from 60th to 50th nationally in defensive rating, and 76th to 21st in rebounding. Poffenbarger and McLean deserve credit for making that happen.

“I feel like defense has always come a little easier to me than offense,” McLean says. “Just making sure that I have my teammates’ back and that they can depend on me to guard their best player.”

Against Dawn Staley’s South Carolina Gamecocks (32-3), Maryland is going to have to play near-perfect basketball if it aims to dethrone the reigning national champs. South Carolina ranks second nationally in offensive rating (122.2), 12th in shooting percentage (47.0) and ninth in rebounds per game with 42.4.

So McLean will need to be the best version of herself. She’ll have to battle for rebounds, use her athletic ability to make key plays and use her defensive skills to take one of South Carolina’s elite guards — pick one, from Te-Hina Paopao to Raven Johnson to MiLaysia Fulwiley — out of the game.

“I think we match up really well,” McLean said. “They’re just like us with rebounding. They’re just like us with guarding. We’re super excited and grateful to be in this position.”