During a scrimmage last week against La Plata, Calvert's Whitney Johnson saw her opponents grimace as the ball rose toward the volleyball net. Johnson leapt into the air, cocked back her right arm and, at that moment, towered above the rest of the court even more than the 6-2 junior does when she stands flat-footed.

Johnson slammed the ball down for a kill past La Plata senior Jessica Smith, who helplessly shook her head.

"I'm sorry," Smith turned and joked to the La Plata coaching staff, "I'm not seven feet tall."

The only thing more omnipresent than Johnson's physical presence, easily the most imposing in the Southern Maryland Athletic Conference, is the word that has followed her since she started playing the sport five years ago -- potential.

As one of the most gifted athletes in the SMAC, Johnson is facing a critical year in her development. Much of the core of Calvert's undefeated Maryland 3A champion team from last season has graduated or been transferred to Huntingtown.

In addition, Johnson understands that she will get more looks from colleges this year, which will force her to become a more complete player and realize the promise she has shown since local coaches saw how talented she was in middle school.

"She's definitely got the greatest potential" among Calvert County players the past decade, Calvert Coach David Redden said. "She'll get recruited by some major Division I schools. This is the year she's got to step up and do it."

Although she has done so much already, Johnson learned over the summer just how much more she has to do to reach her ultimate goal -- play in the Summer Olympics. In July, she was invited to USA Volleyball's High Performance Camp in Colorado Springs, where potential members of the national and junior national teams are nurtured. She was among a handful of players not from the south or west, where volleyball is much more popular.

Johnson looked around at her fellow campers and realized she didn't stick out the way she did on courts back home. She was neither the tallest nor the strongest. She didn't hit the hardest.

"I wondered about the competition and what their standards are," Johnson said. She learned that "you've got to work. There were girls a lot younger than me, like 14 or 15 [years old], and they still could hit as hard as me. You've got to push yourself.

"I saw a 14-year-old girl who was 6-5, and she hit as hard as I do."

Johnson also saw that she could not be just a net specialist. She knows now that she has to become a complete player. That means playing defense and working on her passing, not the flashiest elements of the game.

Redden said Johnson's development has been victimized by her height. Playing on Calvert's junior varsity team as a freshman, Johnson would rarely see the ball because opponents would hit it away from her, thus hindering her defensive improvement. It hurt Johnson's motivation to work on those aspects of her game.

As a result, Johnson did not play a full rotation in games last season. She and Redden both said improving her defense and passing are Johnson's top priorities this season. Redden shudders to think of Johnson becoming like a former player he coached who was strong at the net but did not approach defense with similar enthusiasm. Redden said that player started to get less playing time.

"One of the great things about going [to the camp] was that it exposed her to many skills that were foreign to her," said Cheryl Johnson, Whitney's mother, who accompanied her daughter to Colorado Springs.

Once the high school season starts, Whitney Johnson has another intangible skill to perfect. Coaches said Johnson sometimes has a peculiar disposition on the court. She has no trouble getting fired up for rivals such as Northern and state tournament opponents. But against lesser opponents, Johnson does not project the same intensity; sometimes between points, she will tilt her head sideward, roll her eyes and, to the layman, appear disinterested.

"Some of my expressions on my face are not what I'm feeling," Johnson said. "Sometimes I'm too quiet on the court. I'm mentally into it, but physically, I just don't show it. People think I'm lackadaisical. I play better when I have competition. When I have someone on the other side of the net as good as me, I want to play hard."

Johnson knows that on any given night, a college coach could be scouting her for the first time. She said she can't carry herself like that.

"I want them to look at me, to say, 'That's the player I want,' " she said.

Huntingtown Coach Cheryl Lord, a Calvert assistant last season who has also worked with Johnson in the Southern Maryland Juniors program for five years, said this is another part of Johnson's maturation.

"Some athletes are more innately aggressive," Lord said. "Whitney is a presence on the court just by virtue of her size and ability. She needs to work on exuding that go-go-go attitude. When kids become better and more confident in what they do, they start to show that. I think you'll start to see more of that this year when she's asked to be more of a leader.

"She does have boundless potential, and she's growing into that potential."

To become a more complete player and help defend Calvert's state title, Johnson said she needs to improve her passing. Whitney Johnson is often the tallest player on the court in SMAC play, but she will need more than just height to move to the next level.