So, since apparently we're about to do a new PuRPs poll, I thought I'd post a primer for all the newbies (and non-prospect-heads) who might want to submit their own ballot but don't really know what they're looking at.
Obviously, every person has their own approach to grading prospects. It's a decent place to start with some of the other outfits that rank prospects. John Sickels (who runs minorleagueball.com) is a great place to start; every offseason he ranks the top 20 prospects in each organization. Baseball America posts for free their listing of the top 10 prospects in each organization, and lists the top 30 prospects in their book.
Of course, the point of the PuRPs poll isn't to copy verbatim other prospect rankings, so here's a how-to guide about how to rate prospects. Today I'm going to begin with some basic concepts after the jump.First, I'll talk about the difference between tools and skills. Tools basically refer to a player's innate athletic ability; in shorthand, these are things that can't be taught. Skills refer to anything that can be learned.
To think about the difference between tools and skills: it doesn't matter how much work a player like Prince Fielder gets in the field. He's never going to be a shortstop. Can you imagine him trying? Fielder barely has enough range to play first base, and he definitely doesn't have enough to be a shortstop. Range is a tool -- you either have it or you don't, and if you don't have it, you're limited by the lack of that tool. On the other hand, things like fielding the ball cleanly and making accurate throws are skills. A player can work on those things, but he can't really increase his range.
That's why most traditional scouts focus a lot on tools. If you have a shortstop with average range who's good at making accurate throws and fielding the ball cleanly, and another shortstop with great range who makes a ton of errors, most scouts would prefer to have the latter shortstop. You can teach him to avoid errors, and then you have a shortstop with great range who doesn't make many errors. And if that happens, he's going to be a far better shortstop than the other guy whose range is only average.
But it's difficult to see just how good a prospect's tools are based on statistics. Statistics tell you where a prospect is right now. And with prospects, you're concerned about how good they'll be four or five years down the road moreso than how good they are right now.
So how can you judge tools without seeing them play? Draft position is one (relatively) simple way to guess a prospect's potential. You don't draft a player in the first round if you don't see serious potential in him. Players drafted in the first couple of rounds are generally players whom the scouts see a lot of potential in. Players drafted in later rounds generally aren't viewed as having a lot of potential, though obviously scouts can be wrong from time to time.
And sometimes, a player's draft position is a poor indicator of his potential. Obviously, you can't use it to judge the potential of foreign prospects (who aren't subject to the draft.) And occasionally, a high school senior who's viewed as a tough sign will fall in the draft -- here, signing bonuses can be helpful. A player drafted in the 15th round who gets a signing bonus more in line with a first- or second-round pick probably has far more potential than his draft position would reveal.
Okay. With that out of the way, here are a couple more general concepts to look at when you're reading a prospect's stat line.
Age relative to league: In other words, how old is the prospect compared to the players he's facing? If the players he's facing are older than him, it tells me two things: one, the organization thinks highly of him; and two, he's probably better than his numbers indicate (or at least has the potential to be better.) On the other hand, if the players he's facing are younger, it tells me just the opposite: the organization doesn't think too highly of him and/or he's probably not as good as his numbers indicate.
This is why it's more impressive to see a 20-year-old holding his own in AAA than it is to see a 24-year-old tearing up A-ball. As a rough guide, the average player in low-A tends to be about 21; in high-A, 22 or 23; in AA, 24; and in AAA, 26 or 27 (though that number is pushed upward by the number of AAAA players at that level.)
But age relative to league isn't the be-all, end-all. Don't automatically assume that a player who's young for his level is going to be fine in the long run, particularly if he's really struggling. It's one thing to be hitting .270; it's quite another to be hitting .220. On the other hand, don't automatically write off a player who's old for his level (or at least around the average age for that level), particularly if he's dominating. I'm a bit skeptical of a 22-year-old with a .850-900 OPS in A-ball, but if his OPS is over 1.000 he might be worth a long look.
Park and league context: Of course, we as Rockies fans know all about park effects. But in the minors, league effects are a concern as well: some minor leagues tend to be, on the whole, more hitter-friendly, while others tend to be more pitcher-friendly. Hitters in the AAA Pacific Coast League consistently hit better than their counterparts in the International League, not because they're better hitters, but because PCL parks tend to favor hitters more than IL parks do.
As far as the Rockies are concerned: Colorado Springs is an extreme hitter's park in a hitter's league; Tulsa and Modesto's home parks tend to play relatively neutral, but both the Texas League and California League are hitter-friendly; Asheville is relatively hitter-friendly, but the Sally League is a pitcher's league; Tri-City is a pitcher's park in a pitcher's league; and Casper and the Pioneer League are generally perceived as hitter-friendly.
Positional context: This tends to get overlooked quite a bit, but do consider the position a player plays. Speaking very generally, more demanding defensive positions tend to require less offensive contributions than the easier positions. Keep this in mind when judging, say, a shortstop against a first baseman. A .700 OPS is perfectly fine for a shortstop, but it's not going to cut it for a first baseman.
With that in mind, also note that the position a player currently plays is not necessarily where he will end up. Often, defensive struggles will force a move to a less-demanding position. Or, a prospect may be "blocked" at one position and have to move to another one (usually a less-demanding one, though exceptions exist) in order to get into the lineup.
I'll have more about what to look for with both hitters and pitchers in the next couple of days. I know that PR wants a high level of participation in the PuRPs polls and hopefully, this series will help more people have a better understanding of it.