Disabled List Trends and Team Information

by Jeff Zimmerman on Mar 10, 2010 12:59 AM EST

Trends

I recently found out about an article published named Disability Days in Major League Baseball by Stan Conte, Ralph K. Requa and James G. Garrick in the 2001 American Journal of Sports Medicine about time on the disabled list. The article looked at days on the DL from 1989 to 1999. I took this information and Josh Hermsmeyer's DL database from RotoBlog.com and looked at the trend of DL trips and days on DL since 1989. There is no data on the years 2000 and 2001. I used trips and days per team as there was team expansion during this time period.

Here is the data graphed for both days and trips:

Data in table format:

Year	DL Trip	Average Per Team	Total Days	Average Per Team	Days per Trip
1989	266	10.2	14869	572	55.9
1990	231	8.9	12603	485	54.6
1991	260	10.0	15830	609	60.9
1992	283	10.9	17656	679	62.4
1993	300	10.7	17810	636	59.4
1994	259	9.2	15724	562	60.7
1995	295	10.5	15552	555	52.7
1996	321	11.5	19432	694	60.5
1997	351	12.5	20454	731	58.3
1998	349	11.6	22127	738	63.4
1999	367	12.2	23614	787	64.3
2000	unk	unk	unk	unk	unk
2001	unk	unk	unk	unk	unk
2002	418	13.9	23008	767	55.0
2003	392	13.1	21175	706	54.0
2004	417	13.9	24311	810	58.3
2005	379	12.6	23101	770	61.0
2006	395	13.2	21824	727	55.3
2007	460	15.3	28505	950	62.0
2008	496	16.5	27689	923	55.8
2009	466	15.5	25976	866	55.7

It can be seen (from the graph equations) that the number of trips and days have increased steadily since 1989 by about the rate of 0.3 trips per year and 16.5 days on DL (both per team).

Team DL Data

Using Josh's database, I went ahead and looked at the number of days and trips to the DL for all the teams and here is a graph and table for the data.

The White Sox trainers again stick out as being pretty impressive. At least KC finally has ditched some of their training staff after being the 8 year leader in total trips

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Comments

All the increase per year comes from the increase in the number of trips to the DL . The average number of days per trip seems to be pretty constant. It would be interesting to see if this relationship holds for the teams as well. This may not be a case of more injuries or more severe injuries, but a differing philosophy between teams about how the DL should be used. It also might be useful to have the median days for each DL trip as well as the mean. And the ages of the players going on the DL. It also may be the result of an increased use of long term contracts for older players resulting in more trips to the DL where in previous years an older injured player not on along term contract would be relaeased or would retire.

by pjensen on Mar 10, 2010 10:05 AM EST reply actions

I can get most of the data for using Josh's dataset, but the earlier data is limited to the one article

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by Jeff Zimmerman on Mar 10, 2010 10:10 AM EST up reply actions

Jeff – You might want to contact the authors of the article. Its possible that they would release their database to you if they are not planning any follow up articles. If so , it would make a great extension to Josh’s already great start.

by pjensen on Mar 10, 2010 10:52 AM EST reply actions

Could we split the data

into pitchers and hitters?
Looking at the 2002-2009 results Texas and Baltimore are at the top for total days on the DL. Both have been pitching starved for most of the decade with their starters typically not going too far into games. This has put a lot of pressure on the bullpen which at least for the Orioles resulted in a number of bullpen cogs getting injured after pitching many more innings than the typical reliever (Baez, Chris Ray are two that come to mind) Anybody want to check and see if there is a statistically significant effect?

by OsandRoyals on Mar 10, 2010 11:19 AM EST reply actions