JUPITER, Fla. -- It's 17 days and counting until Opening Day, and the Marlins still have plenty of roster decisions to make.

With a young squad, there is plenty of uncertainty as the organization is measuring whether some of its highly ranked prospects are ready for the rigors of the big leagues. In some cases, position battles are expected to go down to the wire before the 25-man roster is set for the March 29 opener against the Cubs at Marlins Park.

"We're looking at all different aspects of how we manage the roster, if we need to do this or do that," manager Don Mattingly said.

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With so many prospects, the decisions may be tougher for position players than pitchers.

"If you've got a guy you can see is part of your 25, but you don't see him playing on an everyday basis, that's a little tougher," Mattingly said. "Because now he's not getting at-bats, he's not developing and getting the reps."

Before Spring Training started, MLB.com projected the Opening Day roster. Now with the opener quickly approaching, here's a revised predicted roster.

Catchers (1):J.T. Realmuto

All the offseason chatter that Realmuto may be traded can be put to rest. The Marlins have no interest in moving the 26-year-old, but there is some concern over his health. He bruised his lower back last Sunday. If Realmuto is fine, there's no question who will be behind the plate.

First base (1): Justin Bour

Of all the returning players, Bour had the most home runs (25) and RBIs (83) from last year. Miami is counting on the 29-year-old to anchor first and hit cleanup. Mattingly says Bour has 30-homer/100-RBI potential. First, he must establish health, having played in 108 games in 2017 and 90 in '16.

Second base (1): Starlin Castro

Castro's role is to be one of the top offensive producers on the club. He will get a chance, hitting third. The club isn't expecting Castro to hit 30 homers, but he's capable of 30-plus doubles and at least 15 home runs.

Third base (1): Brian Anderson

This call is different than the first projections, because Martin Prado will begin the season on the disabled list. Anderson, Miami's No. 9-ranked prospect according to MLB Pipeline, remains an under-the-radar talent who may surprise as a rookie. He has 20-homer potential. Whether he reaches that number largely depends on Prado. Once Prado is healthy, he will get his share of time at third base. And if Anderson shows any signs of struggling, he could be optioned to Triple-A New Orleans.

Shortstop (1): Miguel Rojas

Rojas has been a utility player since breaking into the big leagues with the Dodgers in 2014. Now, he's the front-runner to start at short, but that could change if JT Riddle is healthy. Riddle had left shoulder surgery last August, and he's easing into game action. Riddle still could win the starting job, but he hasn't played in the big leagues since July 19. So if Riddle opens the season on the DL, Rojas will be the regular.

Utility (4): Tomas Telis , Peter Mooney , Braxton Lee , Garrett Cooper

Telis is out of options, and the Marlins are giving him every chance to make the club. Defensively, he is a work in progress. Mooney would be the surprise candidate to make the squad as a utility player. The 27-year-old plays all over the diamond. Lee, Miami's No. 17 prospect, is a speedster who can play all three outfield spots, and he is already on the 40-man roster. Cooper, also on the 40-man roster, is a first-base/corner-outfield candidate.

Outfield (3): Lewis Brinson , Cameron Maybin , Derek Dietrich

The club's top prospect, Brinson has stood out in Spring Training. He came into camp without the guarantee of winning a starting job, but he is playing his way into the lineup in center field. Converting from infield to outfield, Dietrich projects to start in left. He also should get some chances to lead off. Maybin can play all three spots, but he is tracking to be in right.

Starting pitchers (5): Jose Urena , Dan Straily, Sandy Alcantara , Odrisamer Despaigne , Caleb Smith

A year ago, Urena was fighting for a roster spot. Now, the 26-year-old has been named the Opening Day starter, getting the nod over Straily, who will pitch the second game. There's about 10 others in the mix for three spots. The most intriguing is Alcantara, the 22-year-old with the 100-mph fastball but limited big league credentials. Adam Conley has been in the rotation off and on since 2016, but he was optioned to Triple-A New Orleans. Despaigne is versatile, and he could be in the rotation or the bullpen. Smith was acquired from the Yankees over the offseason.

Bullpen (8): Brad Ziegler (closer), Kyle Barraclough , Drew Steckenrider , Junichi Tazawa , Chris O'Grady , Jacob Turner , Justin Nicolino , Nick Wittgren.

Ziegler has 95 career saves, and the 38-year-old will close. The club expects to carry two long relievers capable of three innings or more. Nicolino, who is out of options, and Turner, who is not on the 40-man roster, each have handled both starting and relief roles in the big leagues. Barraclough and Steckenrider are setup and fallback closer options. Tazawa has handled high-leverage innings. O'Grady, formerly a starter, will get a chance as a lefty specialist who also can throw multiple innings. Wittgren is returning from a right elbow issue.