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