Omar Gonzalez, right, is one of two central defenders for the Galaxy who played at Maryland. The Galaxy gave up 28 goals in 34 matches this year, one of the best marks in MLS history. (ALEX GALLARDO/REUTERS)

Omar Gonzalez and A.J. DeLaGarza are contrasting figures in the heart of the Los Angeles Galaxy’s back line, separated by eight inches and 65 pounds and defined by divergent playing styles.

Other than that, they’re practically brothers.

And three years after playing alongside each other and winning a national title for the University of Maryland, Gonzalez and DeLaGarza are slated to start in central defense for the heavily favored Galaxy against the Houston Dynamo on Sunday night in MLS Cup at Home Depot Center.

“It’s been a great journey,” Gonzalez said, reflecting on their six-year bond, “and it’s not done yet.”

They were teammates for three years at Maryland and lived in the same players’ suite. They were both drafted by the Galaxy, 16 slots apart, and lived together for a year.

Gonzalez, 23, hasn’t budged from the lineup since his arrival. He was named MLS rookie of the year in 2009 and defender of the year this season. DeLaGarza, 24, played regularly his first two seasons and locked down a full-time starting job this year.

With the former Maryland buddies maturing and Todd Dunivant and Sean Franklin providing stability on the corners, the Galaxy recorded the third-finest defensive performance in league history by conceding 28 goals in 34 matches. Last year, the club yielded just 26 in 30 games, fourth-best ever.

After college, “there were questions about both of them,” Galaxy Coach Bruce Arena said. “Omar was supposedly too big and slow and A.J. was too small. But I don’t know too many teams in our league that wouldn’t take both of those guys together in a second.”

At 6 feet 5 and 210 pounds, Gonzalez is an imposing sentry who jars attackers off the ball and wins the aerial game. At 5-9 and 145 pounds, DeLaGarza is a brainy player whose speed of thought — an unappreciated quality in soccer — and technical skills complement his partner’s mighty physical traits.

In the shadows of David Beckham and Landon Donovan, DeLaGarza was tied for second on the Galaxy in regular season appearances and starts (30) and second in minutes played, sitting out just 73 of his 2,700 possible minutes. Gonzalez played one fewer match and missed 11 minutes.

“It’s comforting to play with someone you’ve known for so long and to come here and continue our success,” said DeLaGarza, a 2004 Washington Post first-team All-Met as a forward at Lackey High School.

While growing up in Southern Maryland, DeLaGarza attended D.C. United matches during the club’s glory years between 1996 and 1999. At age 12, he played for a United select youth squad that competed in a Paris tournament. Dave Sarachan, a current Galaxy assistant who was a member of United’s staff at the time, oversaw the roster, which also included 2010 U.S. World Cup midfielder Michael Bradley.

As a freshman at Maryland in 2005, DeLaGarza helped the Terrapins win their first NCAA title in 37 years. A year later, a tall Texan arrived.

“A.J was such an honest, focused player. There was nothing sexy to his game; he just got it done,” Terrapins Coach Sasho Cirovski said. “Omar had the ability to win games, but he was on and off with his concentration.”

During his junior year at Maryland, Cirovski recalled, a few players sat down with Gonzalez and told him:“‘If you had A.J.’s focus, you’d be in the [England] Premier League.’ At that point, the light clicked on for Omar.”

After a 5-3 loss at Clemson in 2008, Maryland allowed just six goals during a 16-game winning streak and registered seven shutouts in the last eight matches. The streak ended with Maryland winning its second national title in four years.

With Gonzalez foregoing his final year of eligibility, he joined DeLaGarza in the 2009 draft. The Galaxy, which had conceded nearly two goals per game the previous season, was desperate for defensive help. Holding the No. 3 pick, Arena thought Gonzalez might go first or second. Instead, he slipped into the Galaxy’s hands.

DeLaGarza was also high on the Galaxy’s list, but with no additional picks until the third round, Arena traded two future selections and veteran defender Ante Jazic to Chivas USA in order to claim the other Terrapins defender in the second stage (No. 19 overall).

Although the Galaxy projected him as an outside back because of his size, DeLaGarza filled a variety of roles as a rookie and started 21 of 30 matches. At the 2009 MLS Cup in Seattle, he came off the bench to replace Gonzalez late in regulation of a game ultimately won by Real Salt Lake on a penalty kick tiebreaker.

Gonzalez maintained his starting job last year, while DeLaGarza filled in at each back line position. This season, with Gregg Berhalter and Leonardo beset by injuries, DeLaGarza reprised his partnership with Gonzalez in the middle.

Gonzalez earned MLS’s top defensive prize and a second straight selection to the Best XI all-league list, helping the Galaxy forge one of the finest regular seasons in MLS history and win its second straight Supporters’ Shield for most points. The club is 14-0-5 at home and has conceded 10 goals.

One final task, though, remains.

“Everyone wants it,” Gonzalez said. “We need that cup this year. It has to be our year.”

Reflecting on their shared experiences, DeLaGarza said: “We played in some big games at Maryland. We’ve played in some big games here. We know how it feels to win a championship and we’re close to getting there again.”