Developing Plate Discipline

I don't think it's an uncommon experience for a fan to wonder about a certain player on their favorite team, "man, that guy has a lot of tools... if only he'd develop some plate discipline!" I know I've had it (*cough* Adam Jones *cough*). How often do those young guys actually improve though? Off to Baseball-Reference's trusty play index for a quick look!

There are 49 players who had a strike-out to walk ratio of at least 4 over the course of their first five seasons (with a minimum of 1,000 plate appearances). Adam Jones is included, as are a number of other current players including youngsters Delmon Young, Kevin Kouzmanoff, and Howie Kendrick, as well as guys on the down swings of their careers like Alfonso Soriano, Jose Guillen, and Pedro Feliz.

 

The combined totals for the group for their first five seasons include a 4.4% walk rate (BB/PA), a 20.3% strike-out rate (K/PA), and 4.6 K/BB. Looking at the totals for season six and later, there's improvement (6% walk rate, 18.5% strike-out rate, 3.1 K/BB). That makes sense though, as batters who didn't improve would be less likely to rack up significant playing time. Several players, in fact, had no plate appearances in the latter category (including Jones and the other younger active players).Taking only the players who had at least 1,000 after their fifth season as well narrows it down to 25 guys.

The average improvements (not weighted be playing time) aren't all that different from the above; +1.3% walk rate, -1.6% strike-out rate, -1.1 K/BB. That's decent, but not all that great considering the hole these guys started in. A few individuals were able to take more significant steps though.

Sammy Sosa almost doubled his walk rate from 5.6% in his first five seasons to 10.4% thereafter (even if a fair bit of that jump was the result of intentional walks). His strike-out rate barely fell - 24% to 23.1% - but he still cut his K/BB rate from 4.3 to 2.2.

The only guys to do better in that last category were Dante Bichette (4.9 to 2.7, largely due to a large cut in strike-outs; 20% to 14.6%) and Craig Paquette (6.2! to 4.1, also largely due to fewer K's; 24.7% to 19.8%). Several other hitters did a nice job improving their games, but none was able to get his strike-out to walk ratio to 2 (about league average).

On the other end of the spectrum, Shawn Dunston went from rarely walking (4.5%) to never walking (2.7%), so even an almost 3% drop in strike-out rate wasn't enough to cut his K/BB rate (up from 4.4 to 5.4).

This isn't to say that this is what to expect from any one player (it's a basic look at the careers of a small group of guys), or that significant progress is impossible. It does leave me a little less sanguine about Adam Jones' chances of becoming an impact hitter unless he starts elevating the ball enough to hit 30+ home runs though.

The full list of 25:

Player	First Five Seasons			Seasons Six & After
	PA	BB%	K%	PA	BB%	K%
Sammy Sosa	2052	5.6%	24.0%	7844	10.4%	23.1%
Juan Samuel	2876	5.3%	21.9%	3788	7.6%	21.5%
Mike Matheny	1278	4.5%	19.7%	3009	6.9%	18.0%
Cory Snyder	2592	5.1%	24.8%	1341	6.9%	26.1%
Alfonso Soriano	2150	4.2%	20.0%	4258	6.9%	20.7%
John Kennedy	1048	5.2%	23.4%	1276	6.8%	16.9%
Matt Williams	2046	5.1%	21.8%	5549	6.6%	16.5%
Juan Encarnacion	1798	4.3%	18.9%	3297	6.4%	15.6%
John Shelby	1015	4.4%	18.2%	2311	5.9%	21.0%
Cito Gaston	2025	5.5%	22.8%	1314	5.6%	17.7%
Dante Bichette	1453	4.1%	20.0%	5402	5.5%	14.6%
Garry Templeton	2764	2.9%	11.7%	5444	5.4%	14.1%
Pedro Feliz	1178	4.2%	18.3%	3366	5.4%	13.3%
Jose Guillen	1943	4.2%	17.3%	4471	5.3%	17.2%
Pat Meares	2077	3.4%	16.7%	1483	5.3%	16.3%
Alex Gonzalez	1829	4.3%	19.6%	3587	5.2%	17.8%
Charley Smith	1188	4.5%	19.6%	1498	5.1%	22.2%
Don Demeter	1141	4.5%	20.5%	2589	5.0%	16.4%
Craig Paquette	1492	4.0%	24.7%	1274	4.8%	19.8%
Tony Armas	1619	4.6%	22.1%	3883	4.8%	21.7%
Corey Patterson	1854	4.7%	23.4%	2244	4.5%	18.8%
Luis Salazar	1912	3.7%	15.4%	2463	4.4%	14.5%
Miguel Olivo	1429	4.1%	24.6%	1629	4.1%	27.5%
Paul Casanova	1757	3.2%	14.2%	1173	3.8%	15.3%
Shawon Dunston	2353	4.1%	17.8%	3923	2.7%	14.8%
Average	1795	4.4%	20.1%	3137	5.7%	18.5%