June 7, 2012

The Process

How to Evaluate Precocious Prospects

by Bradley Ankrom

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This article began as a comparison of Tigers third-base prospect Nick Castellanos and former Padres third-base prospect Sean Burroughs. Castellanos tore through the Florida State League this season, hitting .405/.461/.553 in 55 games, before being promoted to Double-A earlier this week, though his raw power has yet to manifest itself outside of batting practice.

At the same age more than a decade ago, Sean Burroughs was working on a .322/.386/.467 season at Triple-A Portland of the Pacific Coast League, two levels ahead of Castellanos’ recently-vacated Advanced Class-A assignment. Burroughs was also two levels ahead at age 19, making the task of comparing the players a challenge.

Despite posting impressive slash rates at levels he was quite young for, Burroughs rarely dominated. His .291 average in the Southern League in 2000 was only 11% better than the league average, while his on-base percentage and slugging percentages were better by just 17% and 2%, respectively.

Granted, Burroughs was 19 years old and holding his own against competition several years his senior. But in retrospect, the dominance-to-hype ratio at that point in his career appears to have been heavily unbalanced.

Burroughs put up good-not-great numbers in Double-A at age 19, but Castellanos performed better in the Midwest League, albeit against less-advanced competition, in 2011. His batting average (23%), on-base percentage (18%), and slugging percentage (14%) compared to league average were all better than the figures Burroughs posted in Double-A at the same age.

Is it possible to compare the by Burroughs and Castellanos despite the disparity in the quality of the competition each player faced at the same ages? If so, how much, if any, additional credit should Burroughs receive for holding his own against better players? More broadly, is it better for a prospect to be very good or very young?

* * *

Between 1997 and 2011, 280 players had a combined 424 seasons in which they earned at least 300 plate appearances while being at least four years younger than the average player in their league. More than 65 percent of those players reached the big leagues. The average player who did has been worth roughly five and one-half wins above replacement.

To populate the pool of “good” players who were age-appropriate for their leagues, I sought seasons where the player was no older than age 23, one or two years younger than the league average (which skews high), and had accrued at least 300 plate appearances. In order to pick out the elite performances, I filtered out seasons that fell short of the following:

( (AVG/lgAVG)*100 ) + ( (OBP/lgOBP)*100 ) + ( (SLG/lgSLG)*100 ) + ( (((SOR/lgSOR) + (BBR/lgBBR))/2 )*100 ) >= 475

A total of 453 player seasons put together by 384 unique players met the above criteria, and a little more than one-half of those players reached the major leagues.

Type	Players	Reached MLB	MLB  PA	MLB VORP	MLB WARP
Young	280	184	1711	55.7	5.6
Good	384	201	762	24.1	2.4

View complete "young" season pool.
View complete “good” season pool.

Unsurprisingly, the level at which a player performs portends a difference in his future major-league value. By far, more players in the young group qualified while they were in Double-A; the 209 Double-A seasons account for 49.3 percent of the total young player seasons in the study.

Type	Level	Player Seasons	MLB PA		MLB VORP	MLB WARP
Young	AAA	53	2537		75.7	7.5
Young	AA	209	1189		37.0	3.7
Good	AA	91	1373		39.6	4.0
Young	A+	92	1166		40.4	4.1
Good	A+	173	727		21.0	2.0
Young	A	67	964		24.0	3.5
Good	A	144	543		19.8	2.2
Young	A-	3	2536		37.6	4.2
Good	A-	21	426		14.3	1.2
Good	R	24	473		18.3	2.2

Only three qualifying young player seasons were had in short-season leagues—Jorge Cantu (1999), Chris Snelling (1999), and Jose Lopez (2001)—but all three of those players reached the major leagues and have had varying degress of success. Players who had qualifying seasons in Triple-A have gone on to average 7.5 wins above replacement in the major leagues, while those in Class A have experienced the least amount of major-league success, averaging fewer than 1,000 career big-league plate appearances and the lowest WARP in the study.

The players who had good seasons at age-appropriate levels fared significantly worse in the major leagues than their younger counterparts, averaging nearly 1000 fewer plate appearances and, accordingly, about 40 percent less VORP and WARP. These players have also reached the majors at a lesser rate (52.3 percent) than those in the young group (65.7 percent).

The “young” class has produced one 40-plus-WARP major leaguer, third baseman Adrian Beltre, as well as 18 others who have been worth at least 20 wins above replacement. Additionally, two out of five players have earned at least 500 career major-league plate appearances.

WARP	Young	Good
>= 40	0.4%	0.7%
>= 30	2.5%	0.7%
>= 20	6.8%	3.6%
>= 10	13.9%	7.3%
>= 5	21.8%	14.1%

PA	Young	Good
>= 5000	4.3%	2.9%
>= 4000	8.2%	5.5%
>= 3000	15.4%	9.1%
>= 2000	22.5%	14.3%
>= 1000	32.5%	21.9%
>= 500	40.0%	29.2%

* * *

So how should this information influence the way we evaluate Nick Castellanos and Sean Burroughs? We have the benefit of hindsight with Burroughs; he never developed the power that scouts projected for him, totaling just 17 home runs in more than 1,800 major-league plate appearances. Since spending his first four years with the Padres, Burroughs has bounced between the Diamondbacks, Twins, and Rays organizations, accumulating more than 100 plate appearances in only one season. He’s totaled 28.9 VORP and 2.7 WARP over seven seasons, falling well short of the average player from the young pool.

Castellanos didn’t qualify for the “good” pool in 2011, though he certainly would have made the cut this year if he’d hung around Lakeland long enough to collect 300 plate appearances. He has put himself in a position to qualify for the “young” group, however, with the promotion to Double-A and, if history holds true, his major-league outlook is much brighter because of it.