What a difference four years makes.

Heading into 2015, the Cubs had baseball's top-ranked farm system but were coming off five consecutive losing seasons, hadn't been to the World Series since 1945 and hadn't won a championship since 1908. Fast forward to today, and Chicago is riding a franchise-record streak of four straight playoff appearances and still is basking in the glow of the 2016 World Series title -- and its system is one of the leanest in the game.

Fans in the Windy City aren't complaining, of course. The Cubs graduated a stunning collection of young position players to Wrigley Field, and even had leftover megaprospects Gleyber Torres and Eloy Jimenez to trade for Aroldis Chapman and Jose Quintana. Those deals may wind up as one-sided as Lou Brock for Ernie Broglio -- though Chicago wouldn't have won the 2016 Series without Chapman -- and underscore the organization's inability to develop its own pitching.

The Cubs' Opening Day roster may not feature a single homegrown arm. They drafted college arms with 13 of their first 14 picks in 2016 and their top five in 2017, yet their two best prospects are a catcher (Miguel Amaya) and a shortstop (Nico Hoerner). The front office is re-evaluating what it's looking for in amateur pitchers in hopes of developing some mound reinforcements.

Here's a look at the Cubs' top prospects:

1. Miguel Amaya, C

2. Nico Hoerner, SS

3. Brailyn Marquez, LHP

4. Adbert Alzolay, RHP

5. Cole Roederer, OF

Complete Top 30 list »

Biggest jump/fall

Here are the players whose ranks changed the most from the 2018 preseason list to the 2019 preseason list:

Jump: Brailyn Marquez, LHP (2018: 27 | 2019: 3) -- Has better stuff than most southpaws with a fastball that can reach 99 mph and a power curveball that's becoming a plus pitch.

Fall: D.J. Wilson, OF (2018: 9 | 2019: NR) -- Still has some of the best all-around tools in system but hasn't stayed healthy or produced at the plate.

Best tools

Players are graded on a 20-80 scouting scale for future tools -- 20-30 is well below average, 40 is below average, 50 is average, 60 is above average and 70-80 is well above average. Players in parentheses have the same grade.

Hit: 60 -- Nico Hoerner

Power: 55 -- Brennen Davis (Nelson Velazquez)

Run: 65 -- Brennen Davis

Arm: 60 -- Luis Verdugo (Jhonny Pereda, Andy Weber)

Defense: 60 -- Miguel Amaya

Fastball: 70 -- Riley Thompson

Curveball: 60 -- Adbert Alzolay (Riley Thompson)

Slider: 55 -- Yovanny Cruz (four others tied at 55)

Changeup: 60 -- Jose Albertos

Control: 55 -- Paul Richan (Cory Abbott, Keegan Thompson)

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How they were built

Draft: 18 | International: 12

Breakdown by ETA

2019: 7 | 2020: 7 | 2021: 7 | 2022: 6 | 2023: 3

Breakdown by position

C: 2 | 1B: 0 | 2B: 2 | 3B: 1 | SS: 5 | OF: 3 | RHP: 14 | LHP: 3