When I put together my ranking of the top 100 prospects in baseball each winter, I base it on the overall potential I see from each player over the course of his first six years of service in the majors -- the length of time he'd spend with his parent club before reaching free agency -- and apply a discount to players who are further away from the majors. The prospects' potential production strictly in 2016 is only a minor consideration, because weighing it more heavily would lead to a list more populated with low-ceiling players rather than the potential All-Stars I think have more asset value.
To balance that out, I produce another list, this one ranking the top 25 prospects in baseball based solely on how much value I think they might produce in 2016. This list includes one of my least favorite kinds of forecasting (because I don't do it well and have no idea how to do it well): estimating playing time for the next seven months. So you're getting my best guesses -- guesses is the operative term here -- for probably 30 or 40 players underlying the rankings below and my decisions on which players to include. If a prospect you like isn't listed here, it might be only because I don't think he gets the playing time in 2016 to make the list.
I don't rank players with significant professional experience outside of MLB as prospects, so Kenta Maeda (age 28), Byung-ho Park (29), and Hector Olivera (31) do not appear here or on my Top 100. Maeda seems set to be part of the Dodgers' rotation, while Park should be the Twins' starting first baseman, and Olivera may be Atlanta's everyday left fielder after attempts to play him in the infield didn't work out.
With that, let's look at the top 25 impact prospects for 2016:
1. Corey Seager, SS/3B, Los Angeles Dodgers: He's the best prospect in baseball, and he has an actual, bona fide grip on an everyday job. Seager is the odds-on favorite for the NL Rookie of the Year award, and after his huge debut in September, expectations are justifiably high.