In Search of: Top Hitting Prospects

One area where you can gain a significant advantage on your competition is statistical review of minor league players.  Most fantasy baseball players (and I include myself in this group until about a year ago) typically rely on the well publicized top prospect lists without reviewing any relevant statistics.  Due to the increasing popularity of keeper leagues, I've changed my thinking over the past year and have started relying more and more on statistical analysis vs. taking the top names off of prospect lists. 

This process has allowed me to get a jump on top prospects before they become 'household' names.  Last year I was able to grab Matt Kemp, James Loney and Matt Garza long before anyone was writing about them.  Pitching is an entirely different animal when compared with hitting, and in this article I am going focus on the offensive side of the game in order to find a formula that will enable us to quantify top prospects statistically. 

From a hitting standpoint, the review of major leaguers is a different process than looking at minor leaguers in that they are obviously less developed at the age of 17-23 vs. their late 20's/30's.  From a conceptual standpoint, I obviously don't focus on RBI's, runs or batting average.  What I do want to focus on is the same general categories as major league hitters which includes slugging percentages, on-base percentages and plate discipline.

In looking over our minor league database (provided by thebaseballcube.com) that contains stats for the past 20 years, I set out to find a common theme amongst players that have made significant fantasy contributions during their careers.  In other words, I didn't want a list of players that are typically 15th/20th round picks - after all, this is a prospect list and should encompass a potentially dominant group of players. 

In order to accomplish this goal, I focused only on players at the AA and AAA level.  My reasoning for this was that any statistics generated at the lower levels could be attributed to the relatively low level of competition they would be facing.  Initially I decided to look at players with a slugging percentage over .480 and a k/uibb (strikeout per unintentional walk) ratio of under 1.5.  As a result, I found that only about 40% of the resulting players were successful major leaguers and I saw no correlation between the players that ended up on this list and players that have been top 3 round picks during their careers.  At this point, I began to wonder how much of an impact, if any, a player's minor league strikeout rate would have on his major league success. 

To figure this out, I looked into the strikeout ratio of players at the major league level to determine if this was something that would stay consistent throughout a players major league career, or if this ratio would decrease as the player gained more experience at the big league level.  I gathered all major league stats over the past 26 years and sorted them by the player's age. 

The resulting graph (figure 1-1) displays the percentage of AB's that resulted in doubles, home runs, strikeouts and walks by age during this time period.  My expectation was that as player's aged, they would become more and more disciplined at the plate resulting in more BB's per at bat and less strikeouts. 

As you can see from the graph, this is true - strikeout percentages do peak at 19 years old (24.2%) and continue downward until age 40 (15.8%).  While walks follow a similar path, they aren't as drastic, starting out at 6.8% for 19 year olds and improving all the way up to age 40 at 12.3%.  With this information in hand, I decided to ignore strikeout rates and focus solely on power numbers and walks totals.

While taking this information into account, I debated the different ways to capture a players OBP potential until I finally decided to go with ISOBP.  ISOBP is calculated simply by taking a player's OBP minus their batting average.  I decided to use this stat instead of OBP because OBP is inflated by a player's batting average and I wanted a number that represented an isolated walk rate. 

After calculating the ISOBP number for each age group, I filtered out any players with less than 200 AB's,  an ISOBP under 0.080, a slugging percentage under .480 or any players from AA and AAA that were over 23 years old.  The resulting list looked similar to that last one I had created using k/uibb which surprised me.  As I looked through the Brad Cresse's, Matt Craig's and Jason Conti's that were showing up in the results, I noticed that each of these types of players (players without any impact in the fantasy baseball world) had relatively low slugging percentages in relation to the more well-known names on the list.  The list of the other 'no-name' players that were showing up generally had slugging percentages much higher than .480. 

In order to take this factor into account, I decided to increase the slugging percentage to .520 in my query.  The resulting report then looked more like what I was looking for.  Finally!  This final list contained 42 names, with such players as David Ortiz, Jose Canseco, Frank Thomas and Jim Thome.  Of these 42 players, by my count, 11 haven't had any place on a fantasy team, whereas the other 31 have made solid fantasy contributions during their careers.  Of course, this list doesn't include players such as Albert Pujols or Alex Rodriguez, but that is because they were so good that they didn't spend enough time in AA or AAA to qualify. 

With this new formula in hand, I then applied it to the 2006 minor league season and came up with the 4 names you can see below (figure 1-3).  Gordon and Wood are probably not a surprise to anyone that follows minor league prospect lists, but both Votto and Young will probably raise some eyebrows.  Both Votto and Wood will start the 2007 season in AAA, at least to start the season, but are guys to target in the 2nd half if they get called up, or at the very least, at the beginning of 2008.  On the other hand, Gordon and Young are both in line to start the season on the major league roster and are worthwhile picks in the 2nd half of your draft and will both be Rookie of the Year candidates.
 

Figure 1-3
Name	Lg	Lvl	Org	AB	R	H	Dbl	Tpl	HR	RBI	SB	BB	SO	AVG	SLG	OBP	OPS	ISOBP	K/UIBB	Age
Alex Gordon	Tex	AA	Kc	486	111	158	39	1	29	101	22	72	113	0.325	0.588	0.429	1.017	0.103	1.57	22
Joey Votto	Sou	AA	Cin	508	85	162	46	2	22	77	24	78	109	0.319	0.547	0.411	0.958	0.092	1.49	23
Brandon Wood	Tex	AA	Laa	453	74	125	42	4	25	83	19	54	149	0.276	0.552	0.360	0.912	0.084	2.81	21
Chris Young	PCL	AAA	Ari	402	78	111	32	4	21	77	17	52	71	0.276	0.532	0.367	0.899	0.090	1.42	23

The success rate for this methodology is around 75% over the past 26 years, so the odds are pretty good that one of the above players will not turn into the next Frank Thomas or Jim Thome and instead will be the next Josh Phelps or Ruben Rivera, but I will certainly take those odds.  Also - don't look past the stolen base potential that each of these guys posses.  All four are potential 20/20 guys which is just an added bonus on top of their already solid peripheral numbers.

Next week, as we progress through the minor leagues, we will take a look at how this methodology impacts other more well-known prospects in the game.  Yes Delmon, we are talking about you....

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