JUPITER, Fla. -- In the second year of their rebuilding plan, Marlins ownership is dug in for the long run. They’re showing plenty of patience as they go about trying to build a championship-caliber organization from the bottom up.

As they get set to open the season on Thursday at Marlins Park, Miami is determined to stay the course and construct a roster around pitching, defense and athleticism.

The youthful Marlins will be tested right off the bat in a four-game series against Colorado, a team that reached the postseason last year.

With an eye on the future, Miami is not neglecting the present.

That’s why the Marlins' most impactful long-range offseason signings were Cuban outfield prospects Victor Victor Mesa ($5.25 million) and his younger brother, Victor Mesa Jr. ($1 million) -- two players who project to be core pieces for years to come.

Much of the offseason focus was spent on finding a trade match for All-Star catcher J.T. Realmuto, who was dealt to the Phillies days before Spring Training opened for catcher Jorge Alfaro, and pitching prospects Sixto Sanchez (Miami’s No. 1 prospect and MLB Pipeline’s No. 27 overall prospect), left-hander Will Stewart and $250,000 of international signing bonus money.

Infielder Neil Walker, reliever Sergio Romo and outfielder Curtis Granderson were the Marlins' most notable free-agent pickups.

Time will tell if the plan works, but one thing is clear: There is a steadfast commitment to it.

MLB Network recently spotlighted the Marlins as part of their 30 Clubs in 30 Days series and how the organization is building for a brighter future.

What's the goal?

In a word: improvement. The Marlins took their lumps in 2018, going 63-98 in the National League East, a now much improved division. How quickly the club goes from building to contending depends on the pitching. Jose Urena will be the Opening Day starter for the second straight season, and the rotation has depth with some high-end talent. Sandy Alcantara, Pablo Lopez, Trevor Richards and Caleb Smith -- all rookies last year -- will be a big part of 2019. Waiting in the wings at Triple-A New Orleans are prospects Nick Neidert and Zac Gallen.

What's the plan?

Rotation depth is a reason the Marlins didn’t look to sign a free-agent starter. Miami used 13 different starters last season, and if needed, the commitment is there to give the players moving up the pipeline a chance.

Still, the organization is mindful that pitching can be fragile, and unproven starters will have their innings closely monitored. With innings and fatigue a concern, Miami's young pitchers may skip a start periodically. Wei-Yin Chen will start in the bullpen, but might end up being used in multiple roles -- sometimes starting and sometimes being a long-relief option.

What could go wrong?

With youth comes uncertainty, as well as risk. What if some inexperienced starters take steps backwards or struggle with the big league grind? By not signing an established free agent and releasing veteran Dan Straily, the organization didn’t leave itself much of a contingency plan.

Who might surprise?

Several of Miami’s top pitching prospects have shown promise. Richards appears ready to take a big step forward, mixing in a curveball to go with his plus changeup and 90- to 92-mph fastball. Smith, recovering from surgery to repair a torn left lat, was lights-out in Spring Training, but he will be carefully used. Lopez and Alcantara are two 23-year-old right-handers who each have the chance to be middle- to top-of-the-rotation candidates. Based on Spring Training alone, Lopez has been the most impressive. His fastball is up to 97 mph, and his curveball and changeup are improving. Alcantara is the harder thrower, reaching 97-99 mph more regularly.