JUPITER, Fla. — Players carrying bats and wearing expensive sunglasses trudge to and from outdoor batting cages, their spikes click-clacking on the concrete walkways. A handful of fans mill outside the spring training complex gates, hoping for an autograph, or if they’re really lucky, a selfie with a member of the Miami Marlins.

The morning sun shines over the Roger Dean Stadium complex that Miami shares with the St. Louis Cardinals. It’s going to be a hot one. Players, coaches and staff go about their work, share the jokes and brags that are common on a baseball squad, and from the outside, it looks as if it’s just another spring training day.

But for the Marlins, this is not just another spring training. The evidence of that is over their hearts, stitched above the second “M” in “Miami.”

It’s the number 16, which the Marlins are wearing on their uniform tops. They will wear the patch on their chests — not in the usual tribute area of the uniform sleeve — during all 162 games this season.

It’s a season the Marlins will contest without pitching ace Jose Fernandez, who was killed in a boating accident in the waters off South Beach in the early-morning hours of Sept. 25. He was 24.

The death of the immensely popular Cuban-born All-Star eight days before the end of the 2016 regular season rocked the baseball world, the Miami area and the Marlins family. Much of that family has returned as the Marlins try to go on without their pitching leader and mount a challenge to the Nationals and Mets in the NL East.

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“It’s tough,” said starter Tom Koehler, a Stony Brook University product. “But that’s something that we kind of deal with on our own now. We all grieved together and everybody was in the public eye for the last week of the season. We all stayed in contact in the offseason. Helped each other get through it.”

Manager Don Mattingly, the former Yankees star first baseman, opened spring training last month by urging the players to honor Fernandez by competing with the same spirit, passion, and love for the game that Fernandez displayed during his too- brief career and life.

“I don’t think you can go through something like that and not be kind of changed and not affect you,” Mattingly said on Feb. 17, Miami’s first day of full-squad workouts. “Going forward, I think different guys will take different things from what happened last year. What was your relationship with Jose? Or special moments. What your picture of that is. For me, what I like to think about is that little kid. The way he played was with that joy of what you think about when you started playing. That’s really special because you really would like your guys to have that feeling.”

Said closer A.J. Ramos: “We all honor him in our own ways. We all have a goal. We all have something in the way we want to play for him. You want to talk about it with your teammates and the guys that were actually there, that actually knew him, because you feel like you can open up to them.”

Fernandez was a singular talent. In 76 career starts over four seasons — two of which were shortened by 2014 Tommy John surgery — he went 38-17 with a 2.58 ERA and 589 strikeouts in 471 1/3 innings.

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In his final start, on Sept. 20, Fernandez threw eight shutout innings in a 1-0 victory over the Nationals. He allowed three hits, walked none and struck out 12. By one advance statistical measure called “Game Score,” it graded out as the third-best start of his career.

And then the Marlins heard the awful news. They canceled their game for Sept. 25 and returned to work the next night to host the Mets. Leadoff man Dee Gordon, wearing Fernandez’s batting helmet, homered off Bartolo Colon in the bottom of the first and cried as he rounded the bases.

It was Gordon’s first and only home run of the season. It’s a moment few will forget.

The Marlins finished the season, probably in a daze, and went home. When Mattingly choose to address the team en masse during the offseason, it came in an email he sent to every player in late January.

The subject line, as reported by baseball writer Peter Gammons, was “Little Things Mean A Lot,” and it was a call for the Marlins to use attention to baseball detail to emerge as a contender. The body of the letter, Mattingly revealed, was repeated from something then-manager Jim Leyland sent — and not by email — to Pirates players before the 1988 season.

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Of his talk at the outset of spring training, Mattingly said: “You spend a lot of time thinking about what you actually want to talk about. And then you change a lot. It finally just comes. You get it on paper and you feel good about what you want to say.”

The Marlins, who went 79-82 last season, have not finished above .500 since 2009 and have not made the playoffs since winning the World Series for the second time in 2003. They are a young and talented team with an explosive outfield of Christian Yelich, Marcell Ozuna and oft-injured $325-million slugger Giancarlo Stanton, who has appeared in only 193 games in the past two seasons.

Miami beefed up its bullpen by adding veterans Brad Ziegler and Junichi Tazawa and picked up starters Edinson Volquez and Dan Straily. The rotation also will include Koehler, Wei-Yin Chen and Adam Conley. It might not be enough against the stacked Nationals and Mets.

The Marlins know they have to carry on without Fernandez. If they falter, a reminder of his legacy will be over their hearts, stitched above the second “M” in “Miami.”

“There’s moments now where I think individually we have flashbacks,” Koehler said. “We all wish he was here. We understand we have a job to do. There’s 162 games. Nobody’s going to say, ‘Well, they lost a teammate, they lost one of their leaders, let’s take it easy on them.’ So we have to move past that and try to prepare the best that we can. But his memory is absolutely still with all of us.”