Charles Mitchell (0) scrapped his way to 10 rebounds, the most by a Maryland freshman in his debut since 1978, in the Terrapins’ season opener against Kentucky. (Getty Images)

There are times during the Maryland men’s basketball team’s practices when Coach Mark Turgeon chides freshman forward Charles Mitchell. Maybe Mitchell had slowed down, gassed from the endless pace of the afternoon workouts, so Turgeon will jokingly hit a nerve.

Here’s the back story: Mitchell loathes hearing the substitution horn and seeing a teammate beckon him to the bench. It’s nothing selfish, Mitchell says. He’s just such a competitor that it kills him to watch from the sidelines.

“Every time I take Charles out, he’s pissed,” Turgeon said Wednesday. “If he played 39 minutes and 50 seconds and I took him out he’d be mad.”

So if Turgeon judges that Mitchell hasn’t been giving full effort during a practice, he’ll bait Maryland’s rebounding machine into maximum output with a simple challenge.

You know, Turgeon will say, if you practiced a little harder, maybe I wouldn’t take you out as much.

The response usually comes within seconds. Through just two games, Mitchell is tied for the team high with 9.5 rebounds per game. He also had 15 rebounds in 18 minutes during the exhibition against Indiana University of Pennsylvania.

Against Kentucky in the season opener, the Terps snatched an absurd 28 offensive rebounds, a substantial portion of which came simply because Maryland was so erratic on its long-range shots. Mitchell handled the boards that stayed close to the rim, ripping rebounds away from players inches taller, outshining the defending national champions and turning heads on national television. ESPN commentator Dick Vitale compared him to Charles Barkley, attaching Barkley’s “Round Mound of Rebound” nickname to the 6-foot-8, 260-pound Mitchell.

Mitchell’s 10 rebounds against the Wildcats were the most rebounds by a Maryland freshman in his debut since 1978, when Buck Williams posted 13 against Bucknell. Williams won the ACC rookie of the year that season and led the league in rebounding.

Among the Terps’ four freshmen, a close-knit group that entered College Park together with massive aspirations for the program’s future, Turgeon considers center Shaquille Cleare to be the backbone. But Mitchell is the ringleader, the goofy giant with the outsize personality and youthful energy.

As scary as it sounds, Turgeon says Mitchell’s not even playing well yet. His rebounding has been top-notch, but Turgeon sees room for improvement around the rim, both offensively and defensively.

“I think there’s so much more to that kid than we’re getting,” Turgeon said. “I think you’ll see it as the year goes along.”

Already, Mitchell has morphed into an oak tree, chopping fat and adding muscle this offseason. Practicing against James Padgett and Alex Len gave him a wake-up call early on. A year ago, Mitchell said, he probably couldn’t have lasted eight minutes in a college basketball game. Now? He could probably do 40 minutes. Maybe 39 minutes 40 seconds. You know, for a 20-second water break somewhere in the middle.

“I have a winning spirit,” Mitchell said. “I try to do anything to help my team win. I’m not a selfish person at all. I love just helping my team win. If I was on the court for two seconds, I would be all over the floor for a loose ball, anything to help my team win.”

So when Turgeon jokes in practice, Mitchell internalizes it as motivation. I’ll show you, Coach.

“It’s like proving a point to someone, like when you’re a little kid,” Mitchell said. “Just showing him I care a lot about winning. I guess he knows that, but he picks on me a lot about it in practice.”

Maybe so, but Turgeon has already displayed full confidence in the Atlanta native, playing Mitchell throughout the stretch run against Kentucky, while the Terps battled back from a 13-point halftime deficit. Had Maryland led, Padgett might have been in the lineup, providing better defense and more accurate free-throw shooting. But since his team fell behind, Turgeon felt Mitchell gave them a better chance for a comeback.

“He has extreme confidence,” Turgeon said. “He knows he belongs out there. These kids play AAU ball all the time against top players. Where he went to high school, it’s won many state championships. He’s played at a high level. He doesn’t really fear anybody and expects to do well.”