The anonymity of the streets of Manhattan dissolves once Marquez, wearing the No. 4 jersey of a central defender, steps on the field at Red Bull Arena in Harrison, N.J., where his Red Bulls (4-1-3, 15 points) will face Chivas USA (2-3-3, 9) on Sunday night. With his move from the deep midfield to the center of the defense, Marquez has brought a supreme serenity to the game and helped solidify a back line that has allowed only three goals in eight Major League Soccer matches this season. He rarely makes a bad pass or a bad decision on the ball, and he has a keen sense of anticipation. The term soccer IQ is vastly overused, but in this case, Marquez is an Einstein.

“Playing next to Rafa everyday is first and foremost an unbelievable learning experience,” the club’s second-year defender Tim Ream wrote recently in a posting on The New York Times’s Goal blog. “Learning from a player who has played at the highest level for so long is a different animal. I feel more confident this year in my positioning than I did all of last year. Maybe you can attribute that to having a year under my belt, but a lot of that has to do with playing next to Rafa.”

Marquez, 32, made his professional debut at 17 in 1996, in Mexico with Atlas. Then he became one of the first Mexicans to succeed in Europe, first with Monaco in France, then with Barcelona in Spain, where, in 2006, he was the first Mexican to play on a club that won the Champions League title. He played seven seasons with Barcelona, winning 12 titles while appearing in 242 games, the most of any non-European player in club history.

“When I had a chance to go to Europe, I didn’t care what team or what country,” he said. “But it is very difficult for players to leave the Mexican league. There are many issues, but in Mexico, if you are a soccer player, you are very famous, make a lot of money and people treat you like a king.”

Injuries and changing circumstances made Marquez and Thierry Henry expendable to Barcelona. After last year’s World Cup, Henry signed with the Red Bulls for $5.6 million a year, No. 2 in the league behind David Beckham. Then Marquez ($4.6 million, No. 3 in M.L.S.) joined the club. Marquez turned down offers from Manchester City, Bolton and Juventus, among others. And although he and Henry struggled to regain their strength and fitness last summer, most of the attention from the news media and fans was focused on Henry — then and now.