Iwakuma leads the league with a 2.60 ERA, followed by Hernandez at 2.69. It's the fourth All-Star selection for Hernandez, who didn't pitch last year at Kansas City or the previous year in Arizona.
"I think I'll be able to pitch," Hernandez said.
It's the first All-Star selection for Iwakuma, who signed with the Mariners before last season.
"You can see my smile," he said through a translator. "I'm very, very happy."
Iwakuma isn't likely to pitch in the game in New York because he is on turn to start Seattle's final game before the All-Star break, leaving him inadequate time to rest and recover.
"It's unfortunate to not be able to pitch," he said. "At the same time, I want to enjoy the atmosphere."
Wedge was gratified that his top two starters made the All-Star team.
"They're the top two in the league in ERA," Wedge said. "You're talking about masters of consistency. You feel good every time they go out there. They're very different in how they pitch and what they do, but both of them have gotten to the point that they've mastered what they do."