Every year, there are a few guys who start the year well down their own organization’s top prospects lists, only to end it comfortably in experts’ Top 100 lists — and they usually fall into two different categories. First, there are the players who have tools, but just have not put the performance together. And when I say this, I’m not talking about your elite level toolshed players like Bubba Starling and Aaron Hicks, I’m talking about that next level down. The second group are the guys who we thought we had pegged, but were wrong. For example, maybe it’s a command/control pitcher who jumps up a grade or two in velocity. Or a hitter who was thought to have 40-45 power and is now hitting bombs left and right.

This brings us to the important question here. How do we spot these guys before our league mates do? To do this, you need to first get stats and then get context. When looking for stats to tell me who some possible pop-up prospects are, I’m looking more closely at certain leagues and certain stat categories. Now by no means is this an exact science, but the two minor league levels most likely to provide a pop-up prospect are Double-A and Low-A. This usually happens because, excluding the jump from AAA to the Majors, the moves from short-season ball to Low-A and from High-A to Double-A are generally regarded as the most daunting in the minor leagues. This fact causes the trajectory of these players’ stocks to go higher. As far as stats go, I’m looking most closely at strikeout rate for pitchers and total bases for hitters. Obviously those aren’t the only ones I’m looking at, but they are often a good place to start.

The context first comes from checking the player’s age. If it’s a 24 year old in Low-A, I’m not very interested. If it’s a 22 year old in Double-A, now I’m a lot more interested. Then comes the qualitative information from writers who cover minor league baseball – guys like Kevin Goldstein at Baseball Prospectus, Keith Law at ESPN, any of the guys at Baseball America (especially Ben Badler for international guys). There are plenty more good ones, but I’m not going to list all of them out here. You’re looking for first-hand reports – something substantial. Maybe a velocity spike, a mechanical change or just a change in approach. Anything to give substance to what you’re seeing on the stat pages.

If you keep an eye on these things as the minor league season starts, and have roster spots to burn, you can jump the gun on these pop-up guys. And for some examples, let’s check out what you would have seen in April 2012:

Alen Hanson (Low-A, Age 19) – .410/.441/.695, 4 HR, 10 SB, 73 TB

@BenBadler on 4/15/12: Pirates SS Alen Hanson with another home run today in Low-A. That’s 4 HR in 11 games. Had 4 HR in 123 career games coming into 2012 #sleeper

Tyler Austin (Low-A, Age 20) – .345/.383/.828, 9 HR, 3 SB, 72 TB

Kevin Goldstein on Tyler Austin, 4/16/12: He has nowhere near the tools of some of his Riverdog prospect brethren, but the bat stands out, and is very much for real.

Dan Straily (Double-A, Age 23) – 28 IP, 35 K, 9 BB, 3.21 ERA, 24 hits, 1 HR

Gregory Polanco (Low-A, Age 20) – .286/.343/.495, 5 HR, 10 SB, 45 TB