Taking on the Nationals on the road presents an immediate challenge.
So what would constitute a successful season?
"Obviously, our goal is to win," manager Mike Redmond said. "We're trying to win as many ballgames as we can. We've got to focus on development. We've got a lot of young guys. Guys who have to get better, and have to improve. At the same time, too, we're developing with a focus on winning."
The Marlins finished 69-93 a year ago, which prompted the makeover of the roster.
On Monday, nine of the Marlins' 25 players celebrated their first big league Opening Day -- Jose Fernandez, Rob Brantly, Donovan Solano, Adeiny Hechavarria, Wade LeBlanc, A.J. Ramos, Justin Ruggiano, Alex Sanabia and Chris Valaika.
Redmond is experiencing his first opener as a manager, and Tino Martinez as a hitting coach.
The Marlins enter the season with the youngest rotation in the National League and second youngest in the Majors. Their starting five's age averages 26 years, 62 days. Only the A's (25, 3) rotation is younger.
Miami's active roster is the seventh youngest at 29 years, 23 days.
Redmond, the youngest manager in the NL, has received numerous well-wishes from friends, including Mike Lowell and Braves manager Fredi Gonzalez.
"A lot of guys around the baseball world who I've been in contact with texted," Redmond said. "I've been through enough of these as a player, but I think everybody is a little nervous. I know as a player I always got a little nervous. It's more just excitement and getting this thing going."