MASH Report: DL Trends and Re-Injury Rates

Today’s MASH edition is brought to you by some questions I hand listening to Ringer’s The MLB Show podcast featuring Ben Lindbergh and guest Stan Conte (former head Dodgers’ trainer). I would recommend listening to the entire podcast as there is quite a bit of information on injuries. From the podcast, a couple of pieces of information were mentioned by Conte I just wanted to verify them.

The first piece of information I will examine is if short duration injuries are staying relatively constant over the years while the number of longer term injuries are on the rise. This is a fairly easy check. First, here are DL transaction count grouped by 30-day intervals with the exception of all trips over 120 days are grouped together. I have included the trend lines to show any changes.

Just by looking at this graph, it would seem like the upward trend in the less-than-30-day bin and 30-to-60-day bin has the biggest change, but the greater than 120 bin has a sneaky rise from an average of average of 53 trips (2002 to 2006) to 63 trips (2007 to 2011) to 70 trips (2011 to 2015). These add up considering the number of days involved.

Now here are is the number of days lost instead of DL trips.

Now it can be seen how the long trips dominate the increase, but they aren’t all the increase. The average total number of days on the DL increased from 24430 days from 2002 to 2006 to 28846 day from 2011 to 2016 (difference of 4416 days). Now the average number of days lost to the long DL stints went from an average of 8514 days to 11391 days over the same time frames (difference of 2877 days). The long DL trips make up most of the jump (65%), but there is still some increase from other groupings.

The next topic is injury recidivism. It has generally been understood that the best predictor of future injury is a previous injury. Conte mentioned some injuries, like hamstrings, are more likely to bother players in future seasons. This is also not that hard to track.

The following table ranks an injury, grouped by pitcher or hitter, on the likelihood of the player going on the DL after spending time on the DL the previous season for the same or similar injury. I will start with the hitters.

In all, five locations see an above average recidivism rate with knee and back injuries having a significantly higher than average rate. Some of the better fantasy options which had these two injuries in 2016 are Lucas Duda (back), Andrew Benintendi (knee), Jose Bautista (knee), Jung Ho Kang (knee), Shin-Soo Choo (back), and Austin Jackson (knee). At the season’s end, I will provide a detailed DL list for reference to help target the potential injury risks.

Now for the pitchers

No surprise at all to see elbow and shoulder injuries top the list. The next three injury types (knee, back, leg) are the same as the top three hitter injuries. Knees, backs, and leg injuries seem to reoccur.

The preceding re-injury rates have my wanting to redo my injury chance predictions, but that will have to wait for a future article.