The Drafts That Exceeded Expectations

As we in baseball know, the Rule 4 Draft is a strange thing. We go into the draft expecting the best team to get the top player (assuming no signing bonus or injury concerns arise). Players are drafted and the immediately rocket into the Top 100 prospects list despite not playing a game. Yet we simultaneously know that players from all picks in the draft (within reason) can become stars, and all picks have bust potential.

The teams at the top of the draft get the pick of the crop. If they get a top player out of it, no one is really all that surprised because it's supposed to happen. However, when a team picks up a guy at the tail end of the first round, and he turns into a star, we react with a little more surprise and will talk about him as a good value, but he was still a 1st rounder. But when a guy gets drafted out of Texas State University in the 8th Round, right after Cody Burns, and turns in Paul Goldschmidt, that's some extreme value there.

Values like that seem to come along every year. But the question becomes, which draft class had the highest value above what was expected? Which teams managed to find the diamonds in the rough? In addition, how do we know what to expect from a draft pick?

Best Drafts By WAR/Season

The easiest starting point for determining the best and worst draft classes by value above expectation is by looking at the WAR/Season. In this case, rWAR is used for the draft results as pulled from Baseball Reference. Further, we're limiting our search to only the first 10 rounds of the draft, and are only looking at the 1990-2010 drafts.

The leading 2006 Rays draft managed to produce three productive major leaguers: Evan Longoria (1st Round, 3rd pick, 38.5 career rWAR, 5.81 WAR/Season), Alex Cobb (4th Round, 3rd Pick, 7.1 career rWAR, 1.94 WAR/Season), and Desmond Jennings (10th Round, 3rd Pick, 11.7 rWAR, 3.02 WAR/Season). However, the 2009 Angels drafted Mike Trout, Tyler Skaggs, and Garrett Richards, so they may be on the way to passing the 2006 Rays. In addition, the Angels's total includes Patrick Corban and Randal Grichuk, whom they traded away. However, since the point of this exercise is identifying the teams who are getting the best value, even if it gets traded away, this is a reasonable inclusion.

On the opposite end, the 1994 Phillies drafted four players who reached the majors, all of whom had negative WAR. The 1997 White Sox failed to sign 2nd Round pick Jeff Weaver (who would go on to have 15.5 career rWAR), had six total 1st Round and Supplement 1st Round Picks, and still wound out on -1.77 WAR/Season.

Of course, the above table fails to account the different number of draft picks that teams received in the first 10 rounds, so we'll instead adjust things by looking at the WAR/Season/Draft Pick.

Of course, both of these results fail to account for the expectations of a draft pick. The team with the top pick should be expected to get the best player, or at the very least, they have the first shot at him. A player picked in the 10th Round probably isn't expected to be much beyond a career minor leaguer. How do we account for this expectation in determining the best draft class for value?

Expectations of a Draft Pick

I won't go into the details of the statistical technique used, but the general idea behind determining the expectations for a draft pick are outlined in my previous article on drafting extrema. Again, if you're interested in the statistical method used, feel free to contact me and I'll be happy to explain.

Once we find the distribution of WAR/Season for each draft pick, we can calculate the distribution for the entire draft class for that year (at least the first 10 rounds). As doing so would require some very tedious calculations, I will skip the gory math. However, if someone wants to approximate this distribution, you can do so by sampling from the individual pick distributions and summing their total WAR/Season.

Best (And Worst) Drafts By WAR/Season Above Expectation

Accounting for this, we can calculate the WAR/Season above the expectation that a team got in their draft, which can be looked at as a measure of value. Not surprisingly this list has several teams picking near the bottom of the round who find a star (a la Mike Trout), or teams who find a star in the later rounds (Such as Paul Goldschmidt). This is because these teams are getting a lot more value out of a position where value is not necessarily expected. Conversely, the bottom of the list consists of teams with the top few picks that fail to get any value out of their draft.

Not surprisingly, the 2009 Angels draft class comes out on top. In fact, in future years this class may look even more impressive if Skaggs, Richards, Grichuk, and Corbin continue to develop.

As is well known, getting value out of the draft can be difficult. There are so many uncertainties in the development of players that identifying that high value player can be near impossible. But values can be found all throughout the draft, and finding one can help a team build a solid base for the future (assuming they hold on to the talent).

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Data courtesy of Baseball Reference.

Stephen Loftus is an editor at Beyond The Box Score. You can follow him on Twitter at @stephen__loftus.