Miami lost several key pieces this offseason, and in a handful of deals lost pitching prospects Andrew Heaney, Anthony DeSclafani, and Brian Flynn. As they were rebuilding, the Marlins had a top rated farm system, but according to ESPN's Keith Law, Miami's system is ranked 24th heading into the season.
The Marlins' rightfully receive credit, as Law notes, because of their ability to turn young prospects into major league talent quickly. Jose Fernandez and Giancarlo Stanton both support that, as the pair both quickly worked their way through Miami's minor league system. Marcell Ozuna also made the jump from Double-A Jacksonville.
Tyler Kolek and Justin Nicolino will likely open the season as Miami's top pitching prospects, with J.T. Realmuto at the top of the list of offensive prospects. Miami is notably agressive with regard to its prospects, and Nicolino and Jose Urena may make their major league debuts at some point in 2015.
After extending Stanton in November, the Marlins have invested in winning now, since Stanton could opt out after six seasons. Whereas the Marlins were interested in adding prospects in the past, all offseason the club has sought major league talent to improve its roster. Mat Latos, David Phelps, Martin Prado, Dan Haren, and Michael Morse should help the Marlins improve in 2015, but even if the club does not have an ideal start to 2015, it may not consider trading away major league pieces in exchange for prospects.
Although they lost numerous prospects, the Marlins only dropped five slots. Law ranked Miami 19th before the start of 2014, which at the time was notable because Heaney and Nicolino were seen as key rotation arms. At the Single and Double-A levels, Miami does not have a ton of depth. But since the Marlins are in "win now" mode, the fact that they are close to the bottom of the league suggests they are committed to being competitive for at least the next few seasons.
Miami does not have a top farm system, according to Law. But if the Marlins want to compete consistently, that should not prove to be an issue.