Nationals pitcher Gio Gonzalez has so many followers among his family and friends that even the family barber comes out to cheer for him. (Toni L. Sandys/THE WASHINGTON POST)

Gio Gonzalez heard the familiar, piercing cheers while standing on the pitcher’s mound, coming all the way from Section 211 of Roger Dean Stadium. Gonzalez, 26, felt a small dose of the mortification any Little Leaguer could relate to: His mother would not stop yelling his name.

“They were definitely in the top of the stands,” Gonzalez said. “My parents, I had to tell them, ‘Turn it down up there. We’re all grown men now. This ain’t Khoury League anymore.’ ”

When the Washington Nationals traded for Gonzalez this December, they traded, too, for the unapologetically boisterous and unabashedly loyal extended family that comes with him. The Nationals got to meet many of them Sunday afternoon, a clan that included Gonzalez’s parents, his grandfather, a cousin, an uncle, at least two aunts, several baseball players from Hialeah High and the family barber.

As he became an all-star in Oakland, his family watched him from afar. Now that he’s stationed in the National League East, they plan to snap up season tickets to Nationals Park and to invade the Miami Marlins’ stadium with a group, they say, that will approach 2,000.

“Less than an hour?” Max Gonzalez, Gio’s father, said. “You can’t beat this with a stick.”

Gonzalez relished the chance to pitch so close to home, and he carried extra anticipation into his start. “Everybody in Hialeah is coming,” he said Saturday morning. Before he threw his first pitch, he doffed his cap to some Hialeah players standing behind the backstop.

“I was really excited,” Gonzalez said. “This is going to be amazing. To represent the city of Hialeah and the people down in South Florida, it’s going to be awesome.”

As his entourage hollered from around the stadium, Gonzalez did not disappoint. He fired four scoreless, two-hit innings against the St. Louis Cardinals without walking any and striking out two, his fastball zipping between 90 and 93 mph. Gonzalez has not allowed a run in seven spring innings, and Manager Davey Johnson called him a candidate to start opening day.

“He’s been nothing but superb all through the spring,” Johnson said.

Gonzalez grew up in a tight-knit community in Hialeah, his Jersey-tough father Max and doting mother Yolanda serving as the patriarch and matriarch. Gonzalez treated his cousins like brothers and friends like cousins. Max and Yolanda took in one friend of Gonzalez’s, a kid from a broken home named Jon Hernandez.

Hernandez played sandlot ball with Gonzalez and grew up to become the pitching coach at Hialeah High. Gonzalez now sponsors the team, supplying the players with cleats and uniforms from Under Armour. Sunday, several players joined Hernandez as guests of Gonzalez’s.

“It’s phenomenal how he hasn’t forgotten where he’s come from,” Hernandez said. “Family has always been first — family first, baseball second.”

In high school, Gonzalez transferred out of Hialeah High following his junior season after a dispute between his parents and the coach about his brother’s playing time. He played his senior year at Monsignor Pace, and the coach there suspended him for the playoffs after Yolanda protested his brother’s playing time. If one Gonzalez perceives you have wronged one of them, you have wronged them all.

As Gonzalez ascended, from high school stud to major league all-star, his parents have not stifled their support. “I told him I didn’t drive an hour to sit there and be quiet,” Yolanda Gonzalez said, laughing. “You’re at a ballgame, not a funeral.”

Nationals officials have internally discussed making sure Gonzalez’s family does not cross the line from supportive to meddlesome. During a rain delay Sunday, the Hialeah High players sought refuge and waited for Gonzalez in a lobby connected to the Nationals clubhouse. Gonzalez’s family followed behind.

Max Gonzalez carried an expensive black box containing a Lamborghini watch, a gift for his son. After Gonzalez signed his five-year, $42 million extension, he bought himself a Lamborghini, his mother a Rolls Royce and his father a Ferrari. “That’s a nice car,” Max said.

Soon, 20 people stood in the entrance to the clubhouse and in front of the door to the umpire’s locker room, a restricted area. After two minutes, a clubhouse attendant barged into the room.

“I need your attention,” the clubhouse attendant shouted. “If you don’t have a credential, you have to leave this hallway. There’s too many people in here.”

The family lingered another few minutes before another clubhouse attendant spoke. “I only see six people here with a credential,” he said. “I’m sorry to be a jerk, but you need to leave.” The clan took refuge under the bleachers.

“It was the Gio show, right?” Max said.

From the moment Gonzalez joined the Nationals, he has anticipated the first start he’ll make in Miami, in front of his family and home town. Sunday offered a preview.

“Imagine,” Gonzalez said. “There’s going to be more. I definitely got a nice, big fan base down in Florida.”