Plate Discipline

As usual, there has been a lot of talk this winter about plate discipline and the talk continues as spring training begins. Plate discipline or strike zone judgement means different things to different people. One simple definition would be the recognition of balls and strikes and the ability to react accordingly. That is, swing at strikes and don't swing at balls.

Another way to define plate discipline would be the ability to balance patience with aggressiveness. Jim Leyland talked about this in discussing Curtis Granderson this week. Leyland wants hitters to work the count and make pitchers throw more pitches but he also wants them to swing when they see a pitch they can hit. Being able to maintain this delicate balance is an important skill.

Another aspect of plate discipline is a batter's approach with two strikes and this is the number one item on which Leyland wants batters to work this spring. He wants players to shorten up their swings a bit and concentrate on making contact once the count reaches two strikes. A good two strike approach might also include fouling off strikes in order to extend at bats.

Using the retrosheet play by play data base, Billfer investigated the Tigers performance in 2006 after they reached two strikes. He discovered that, while some Tigers (e.g. Placido Polanco) did better than others (e.g. Curtis Granderson), their team performance relative to the league was the same with two strikes as it was in other situations. That is, they slugged better, walked less, got on base less and struck out more than other teams regardless of the count.

One simple way to try to measure overall plate discipline is to look at strikeout/walk ratio. In 2006, the Tigers drew the second fewest walks (430) and had the second most strikeouts (1,133) in the American League. That comes out to a league worst 2.63 k/BB ratio. The league average ratio was 1.96 or about two strikeouts for every walk. By that measure, the Tigers had very poor plate discipline last year.

Table below lists the k/bb ratios for Tigers hitters in 2006. It shows that only Carlos Guillen (1.23) and Placido Polanco (1.59) did substantially better than league average. Magglio Ordonez (1.93) and Sean Casey (2.10) were right around the league average. If you include his time with the Pirates, Casey had 33 BB and 43 k for a 1.30 ratio which is closer to his career ratio of 1.21.

The rest of the team including Marcus Thames (2.49), Curtis Granderson (2.64), Brandon Inge (2.98), Chris Shelton (3.15), Omar Infante (3.21), Rodriguez (3.31) and Craig Monroe (3.41) was much worse than league average. It won't be easy for them to dramatically improve these ratios but the hope is that through better discipline, some of these players can get closer to the 2 strikeout to 1 walk league norm.

One player who should help a lot in improving the team ratio is Gary Sheffield who has an astounding 0.75 career mark. This is just one more reason why I'm looking forward to seeing him the Tigers line-up this year.


Table: K/BB Ratio for Tigers in 2006

Player	PA	K	BB	K/BB
Guillen	622	87	71	1.23
Polanco	495	27	17	1.59
Ordonez	646	87	45	1.93
Casey	196	21	10	2.10
Thames	390	92	37	2.49
Granderson	679	174	66	2.64
Inge	601	128	43	2.98
Shelton	412	107	34	3.15
Infante	245	45	14	3.21
Rodriguez	580	86	26	3.31
Monroe	585	126	37	3.41