But while Kaupe was surprised he was picked early, he wasn't shocked that he was a relative unknown. That's how it works when you play baseball close to 2,500 miles from the nearest Major League ballpark. That's how it works when you're a high school phenom from Hawaii.
"The guy at MLB.com said the perfect quote for me. He said, 'I hardly know this kid.' And that's exactly why Hawaii kids don't get that much exposure," Kaupe said. "But when we make it, you don't make it for your hometown, you don't make it for Wailuku or Maui, you make it for Hawaii."
As a senior at Baldwin High School, on the island of Maui, Kaupe never struck out. Not once. He hit .511 (23-for-45) with two home runs and 21 RBIs this season.
Kaupe's coach at Baldwin, Jon Viela, said the 18-year-old standout can play any position on the field. In addition to playing second base and shortstop, he served as the team's closer, reaching 87-88 mph on the radar gun, although Viela tried to limit his time on the hill.
"He was too valuable in the field to put on the mound," Viela said. "Brandon, the skill he has, he can play anywhere on the field. There were times in his sophomore year we played him in center field because of his speed and arm strength."
Kaupe is still a raw talent, but Mets vice president of player development Paul DePodesta said he liked everything about him. DePodesta flew down to watch Kaupe work out and play in a doubleheader, during which the versatile infielder hit an inside-the-park home run.
"We think we have a leadoff-type guy," DePodesta said. "With his work ethic, he really has a very high ceiling for us."
Kaupe has been playing baseball since his mother, Joy, enrolled him in the sport when he was 3 years old. His father, Bernard, a former baseball player from Hawaii, took over coaching him when he was 5, and has been a strong influence in his life.
Kaupe was a two-sport athlete at Baldwin, playing strong safety, running back and kick returner for the football team. He had five return touchdowns and rushed for 780 yards on 21 carries in his senior season. But baseball always took precedence.
He traveled with Team Hawaii head coach Duane Eldredge to the mainland to play in the Senior Fall Classic in Arizona. It was in that tournament where the Mets first caught a glimpse of their fourth-round pick.
"If it wasn't for that, nobody would have ever seen him, except for in baseball tournaments in Hawaii, when a few scouts come," Bernard Kaupe said. "Playing away from the mainland, it's hard for Hawaii boys to get recognized. Hats off to coach Duane Eldredge from Team Hawaii. He took my son everywhere and got my son noticed."
Kaupe watched the Draft with his mother, father and sister on Tuesday. After his selection, he was bombarded by phone calls and texts from friends and family, but one stuck out in particular. The Mets called Kaupe to congratulate their new middle infielder from Hawaii on being drafted.
"It was amazing. Everything is still so unreal," Kaupe said. "Everything is happening so quick that it's hard to react to everything that's coming out."
While the Mets' first-round pick, Gavin Cecchini, visited Citi Field and met with third baseman David Wright, the closest Kaupe has been to Flushing is creating himself on a Major League roster in a video game.
While Kaupe didn't have the opportunity to meet any of the current Mets, he's followed the team for a while, modeling his game off former New York infielder Jose Reyes. Kaupe has a bit of time before he thinks about manning Reyes' former spot in the Mets' infield, but for now, he's already paved a path for baseball players coming from his home state.
"The common thing nowadays is high school coaches like to see their kids play more in the [mainland] because of that exposure," Viela said. "Someone like Branden opens up a lot of doors for youngsters here. Branden has set the foundation for a lot of kids."
Ethan Aofsky is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.