Patrick Sibley, 21, was a strong, independent athlete who enjoyed a healthy sibling rivalry with his older brother, with whom he played volleyball at George Mason University.

So if he got off at the wrong Metrorail stop early Sunday, friends and relatives wouldn’t be surprised if he tried to make his way on foot along the tracks of the Orange Line to the next station.

The young man was struck and killed by a train between the Ballston and East Falls Church stops. He was hit shortly before 2 a.m. by a train heading toward Ballston, Metro officials said.

Brother Shaun, 23, said Patrick was headed home from a Clarendon bar to a townhouse that he had just rented for the school year with friends in Vienna. It is unclear where he exited the train and exactly where he was headed.

Patrick, who was known as Pat among friends and relatives, had spent the summer as an intern at a financial institution in Pennsylvania. He and his friends had been moving their belongings into the townhouse Saturday to prepare for the start of school and had gone out afterward, his brother said.

Patrick Sibley (George Mason University Athletics)

Shaun said his brother had left the bar and “just wanted to go home.” He said he thinks his brother, who he said did not have a good sense of direction and wasn’t familiar with the Metrorail system, got lost. He and another relative think Pat got off at the wrong station and tried to make his way down the tracks but became confused.

Knowing his brother, Shaun said, he might have decided to try to run along the tracks to the next station.

“It is more than likely that he thought he could do anything,” Shaun said. “He was a big, strong, athletic kid. He didn’t take no for an answer.”

William T. Rice Jr., a grandfather of the brothers, said of Pat: “Knowing him, I believe he said, ‘The shortest distance between two points is straight ahead,’ and he started on the tracks.”

Metro officials said the incident is under investigation and are not commenting on the case. Pat Sibley is the seventh person to be struck by a train this year, according to Metro.

Growing up in San Diego, the Sibley brothers played sports together. Shaun recalled how in elementary school he was being bullied and pushed around by another kid, and his younger brother defended him.

“He pushed that guy down and told him not to mess with me,” Shaun said. “That’s how he was. Always loyal. Always looking out for me.”

They played on the volleyball team at Natick High School in the Boston area. Their high school volleyball coach, Peter Suxho, said, “Everything [Pat] did was hard work and with a big smile and a desire to become the best player.” By the time he finished high school, Pat was named the most improved player on the team, Suxho said.

After high school, the brothers went their separate ways to college — Shaun to George Mason and Pat to Sacred Heart in Fairfield, Conn., both on scholarships. They played against each other on their respective teams.

When Pat’s volleyball coach said he was leaving the team two years ago, Pat said he wanted a change and his brother helped him transfer to George Mason and get on the volleyball team.

With red hair and blue eyes and standing 6-foot-7, Pat and his brother (6-foot-9) were considered standout players on the men’s volleyball team at George Mason. They helped the team get close to a spot in the NCAA Final Four, but it lost to Harvard in the semifinals.

In a statement from the university, teammate David Lucas said that Pat’s “impact on the volleyball court was unmatched.”

Shaun is finishing a few credits in his senior year at Mason, and Pat, who was interested in a career in finance, was set to start his senior year.

Although the brothers didn’t play every game together, they enjoyed being on the same team. When Shaun switched to another position on the team and then tried to get his old spot back as a starter, he found that his brother had it. Shaun and Pat both eventually played as starters on the team.

In a March article in the MetroWest Daily News, Pat talked about their competition.

“I’ve made it a little tough on him getting his spot back,” he said. “But it’s always friendly, for sure. . . . We are always just trying to push each other to become better players. It makes it a little more fun and a little more intensive, bragging rights at home and whatnot.”

Jennifer Jenkins contributed to this report.