If Yelich gets hot, he could perhaps find himself getting the call up to Double-A Jacksonville later his summer.
Earlier this season, Yelich missed about three weeks due to a concussion. He was cleared to play after two weeks, and he was given another week getting game ready before being activated.
"It drove him crazy. He loves to play," Hammerheads manager Andy Haines said. "He did not handle it very well, because he loves to be on the field. With concussions, everybody knows it's a little bit different than everybody used to think.
"Our medical people were cautious, as they should have been. We sent him to Miami. I thought they handled it great, because if you left it up to him, he would be playing, which he shouldn't have been."
With his two homers on Thursday, Yelich now has nine on the season.
Fernandez, starting for the first time in 12 days, showed signs of why he is so highly regarded. His first pitch of the night was a 95-mph called strike. His third pitch reached 97 mph.
The right-hander also showed some rust, having not made a start in 12 days due to his promotion and several days of rainouts. Still, he collected a win, giving up four runs in five innings with four strikeouts.
Yelich, the Marlins' first-round pick in the 2010 First-Year Player Draft, and Fernandez will represent the Marlins at the Futures Game on July 8 at Kansas City.
"It's going to be a great experience," Haines said. "How grounded as they are, they're both really appreciative and glad to go. I think for them, just to see the other elite players who get the notoriety from other organizations, it will be a great experience for them. Just to be around that environment ... for their development, it will be good."
Fernandez, who was promoted from low Class A Greensboro, was born in Cuba, and he defected into the United States at age 15. The 19-year-old initially didn't know anything about the Futures Game.
Recently, he played in the South Atlantic League All-Star Game, and thought that was it regarding a mid-summer showcase. Marlins director of player development Brian Chattin had to explain what the Futures Game is.
"When he called, I said, 'Thank you very much, but what does that mean?' I just finished the All-Star Game," Fernandez said. "It's going to be amazing. There will be a lot of talent. I love to compete and pitch to big hitters."