The results of statistical studies are often intuitive, but quantifying our intuition can be useful. Last week, David Laurila published an interview with Carlos Beltran that reminded me of plate discipline data that Jeff Zimmerman and I discussed this off-season. First, Mr. Beltran on his approach:

I…concentrate on getting a pitch in an area I know I can handle. If it’s a pitch on the outside corner, I know I can’t do much with that pitch. Unless I have two strikes, I don’t want to swing at it. If it’s a pitch on the inside corner and I don’t have two strikes, I don’t want to swing at it. That’s a pitch where, even if I take a good hack, I feel I’m not going to do much with it. I have to look for a pitch out over the strike zone, in or away. Basically, near the middle.

Prospect discussion revolves around the 5 tools — Hit, Power, Speed, Defense, Arm Strength. The list, in its entirety, is sufficient yet imperfect. As Beltran discusses, his approach is crucial to his success. Intuitively, we know the importance of plate discipline and there is ample statistical evidence to support our beliefs. Walks are nearly as valuable as singles. As the count fluctuates, the run expectancy changes. Harry Pavlidis and Dan Brooks quoted Rockies’ Catching Coach Jerry Weinstein, who stated “[T]he expected runs produced from each plate appearance starting with a strike decreases by .029 runs and increases by .040 for every ball thrown on a first pitch.” Although we discuss a prospect’s approach less frequently, it’s very important to their Major League success.

Beltran specifically discusses his selectivity within the strike zone. Swinging at strikes isn’t enough, however; one must identify the pitches which are most hittable for him and attack them. This off-season, I asked Jeff Zimmerman to run the numbers on another, similar aspect of hitters’ approaches — BABIP on pitches inside and outside the strike zone.

Season ooz-BABIP iz-BABIP 2008 0.264 0.307 2009 0.270 0.306 2010 0.263 0.301 2011 0.268 0.300 2012 0.267 0.301 2013 0.271 0.299 Total 0.267 0.302

Unsurprisingly, putting a strike in play yields a more successful outcome than putting a ball in play. When watching prospects, it’s important to note whether they appear to have a plan at the plate. Since his age-19 season with the Brooklyn Cyclones, Brandon Nimmo has stood out to me as a player who uses his knowledge of the strike zone to put himself into good hitting situations.

The Mets’ outfielder has begun the season with a slash line of .393/.519/.500, a 22:19 BB:SO ratio and a .500 BABIP. Nimmo’s BABIP is unsustainable, yet it would be unwise to believe it was created entirely by luck. Nimmo couples an outstanding knowledge of the strike zone with a selective approach. Rarely, compared to his peers, will the youngster expand the strike zone. And just as Beltran describes, Nimmo will allow a strike to go by if it is outside of his preference — low fastball middle to middle-in.

Conversely, there are some top prospects who too often swing at pitches outside the strike zone. Oscar Taveras not only expands the strike zone, he often puts bad pitches into play. As the numbers above indicate, this approach is not ideal (though hardly fatal). In the minor leagues, where defense is poor and pitches are of a lower quality, it may be easier to succeed with such an approach.

A hitting prospect’s approach is often discussed secondarily, if at all, to his ability to hit for average and power. However, identifying a player’s approach is an essential step in the evaluation process.