Aug 30, 2013; Toronto, Ontario, CAN; Kansas City Royals third baseman Mike Moustakas (8) hits a double in the ninth inning against the Toronto Blue Jays at Rogers Centre. The Blue Jays beat the Royals 3-2. Mandatory Credit: Tom Szczerbowski-USA TODAY Sports

Can Spring Training Stats Spot a Breakout?

We’ve been told time and time again that spring training stats do not matter. We have been told to not make fantasy baseball decisions based off of spring training stats.

But is there a spring training stat that can actually predict regular season performance?

Probably not.

Yeah, but still, let’s look at one anyway that might, just might, be a spring training stat we can use to predict regular season performance. After all, It’s not that spring training stats aren’t meaningful, they’re just less meaningful.


The Dewan Rule

John Dewan – the owner of Baseball Info Solutions – established the following criteria:

  • The player must have at least 200 career at bats in the majors.
  • The player must have at least 40 at bats in the current season’s spring training.
  • The player’s slugging percentage for spring training must exceed his career slugging percentage by at least 200 points.

It’s a 200/40/.200 criteria that has become to be known as “the Dewan Rule.”

The Dewan Rule passes the sniff test when you first hear about it; it at least sounds plausible. A much higher slugging percentage would may might could possibly indicate a higher slugging percentage during the regular season, which would be a huge boon for the fantasy owners of those players.

The problem is that research as shown that you’d have just about as good a shot on a coin flip. The chances of The Dewan Rule actually predicting a breakout is a 50/50 proposition.


Thanks for Nothing

But even though we didn’t discover a magical white unicorn that will solve all our fantasy baseball drafting problems, it doesn’t mean the Dewan Rule is completely without merit. Remember, it’s not that spring training stats aren’t meaningful, they’re just less meaningful.

While the Dewan Rule doesn’t help in any statistically objective sense, it certainly can be a tool in our subjective decision making.

  • Can it not reasonably be inferred that a player with a hot slugging (more on SLG% here) spring is hitting himself into more playing time? At bats matter, so look for clue that a player might be getting more.
  • Can it not be partially inferred that a player with a hot slugging spring is seeing the ball well? You want to see a player come into camp sharp.
  • A hot slugging spring is an indicator that a fantasy owner should dig a little deeper into the player to see if perhaps he’s changed his approach at the plate. This change in approach could lead to a lasting breakout (see Jose Bautista 2010).


I’ll Be Your Research Monkey

At the time of writing, only the Kansas City Royal’s Mike Moustakas and the Cincinnati Reds’ Chris Heisey are approaching the requirements for the Dewan Rule, yet they are still a few at bats shy of the 40 at bats needed.

But keep the Dewan Rule in the back of your mind as you are doing your fantasy baseball research. Better yet, you can follow us on Twitter (@FBCrackerjacks) and I’ll do the research for you, tweeting out any players that have a 50/50 shot of a breakout season.

Tags: Fantasy Baseball Mike Moustakas MLB SLG Spring Training

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