Bobby Boswell spent six seasons in Houston, starting 176 of 188 regular season matches. (Orlin Wagner/Associated Press)

Bobby Boswell departed D.C. United six years ago as a self-described “snot-nosed kid.” He returned this winter with two kids and perhaps the captain’s armband.

Boswell has been asked to set the norms instead of challenging them. His personality remains large; his responsibilities are larger.

Boswell’s second tour in Washington feels like a first — a fresh start with an old team that has retained almost no ties to the club he knew between 2005 and ’07. The only locker-room holdovers: former teammate Ben Olsen, United’s fourth-year head coach, and longtime assistant Chad Ashton.

“I went to the season ticket holder event a few weeks ago and knew more fans than almost all of the [front office and support] staff,” said Boswell, who turns 31 next week. “Everything is new. I feel like we can make this our team and decide where we are going with it.”

Boswell was among seven probable starters — and 11 newcomers overall — acquired after the worst season in United history (3-24-7). He will serve as the cornerstone of a fully renovated backline and a key figure in Olsen’s effort to mold a winner.

Although Olsen has yet to appoint a captain ahead of Saturday's opener against the Columbus Crew at RFK Stadium, Boswell filled that role in each of the two Carolina Challenge Cup preseason matches featuring the primary players.

“He is an extension of our coaching staff,” Olsen said. “He is going to be a guy who understands the pulse of the team, and with our relationship, he won’t be afraid to come knock on my door.”

Boswell was not afraid to make noise in his first spell with United — on or off the field.

An undrafted rookie in 2005, he seized a starting job with the defending MLS champions and, a year later, was voted the league’s best defender. He broke into the U.S. national team, and in 2007, joined the squad at Copa America, the prestigious South American tournament.

Boswell’s reach extended beyond the stadium: He agreed to be nominated for Cosmopolitan’s bachelor of the year contest and was on the cutting edge of athletes engaging with fans through online platforms. He launched and posted irreverent videos, featuring teammates and friends. There were parties and appearances.

“We were a little ahead of the time and people didn’t know how to accept it,” he said. “It’s now a daily part of our lives. When you are the first one, there is some negativity toward it. People have realized social media is more acceptable, there were definitely things I was doing I wouldn’t like if a young guy were doing it now.”

Boswell’s off-field activities caused distractions.

“Sometimes you don’t realize your actions on and off the field can affect not only you, but the group,” he said. “You can have a great Web site and following, but I am a soccer player and I get paid to win.

“I was a snot-nosed kid. It took me going somewhere else to realize what I was doing maybe wasn’t the smartest in terms of getting the product right on the field.”

Boswell’s sideshow seemed to take a toll on his performance and did not sit well with Tom Soehn, United’s no-nonsense coach who benched him a few times in 2007.

By the end of the campaign, both sides needed a change. Seeking a goalkeeper to replace Norway-bound Troy Perkins, United dealt Boswell to the Houston Dynamo for Zach Wells.

It would prove to be a huge mistake: Wells lasted one season and abruptly retired, while over six seasons, Boswell started 176 of 188 regular season matches and helped steer Houston to two first-place finishes and two MLS Cup appearances. Since 2005, no central defender has started more league matches than Boswell (254).

This winter, though, the Dynamo decided not to pick up his contract option, exposing him to the re-entry draft. In the market for experienced defenders, United claimed right back Sean Franklin (Los Angeles) in the first round and Boswell in the second. D.C. also traded for center back Jeff Parke (Philadelphia) and signed left back Cristian Fernandez (Spain).

“A lot of games and years between us,” said Parke, 31, who entered MLS a year before Boswell. “We’re still learning, still getting to know each other. It’s important we get that going now so we can produce some early results.”

Boswell is eager to reestablish roots in Washington. Once a regular on the city’s social scene, he returns with a wife and two sons (3 years old and newborn), and eyes on a suburban house.

“When he first arrived [in 2005], some of the energy and charisma was a little misguided but natural for a young kid,” Olsen said. “He has found that balance of still being a guy who can hold court and also lead. He seems like he is in a good place.”

United notes: Weather conditions forced the squad to practice at an indoor facility in Anne Arundel County on Tuesday. The club plans to train on the artificial turf at Long Bridge Park in Arlington the remainder of the week. . . .

United acquired midfielder Alex Caskey (17 starts in two seasons) from the Seattle Sounders for a 2016 third-round draft pick. Free agent midfielder Reuben Ayarna was released and midfielder Abel Sebele might continue practicing, although he is not expected to receive an offer. Olsen will continue to evaluate midfielder Victor Munoz, a second-round pick from UCLA.