The 2016 Disabled List - part 2 |
1B 2B 3B SS IF | LF CF RF OF UTL | LHS LHR RHS RHR C |
The following chart shows the number of Placements by position that were placed on the 2016 DL. The percentage is the portion of placement to the total on the DL (561). So therefore, RHS (Right Handed Starters) represented 25.8% of all the players placed on the DL in 2016.
The total percentage of pitchers on the DL was 56.0%.
Not surprisingly, all pitchers (Starters and Relievers) head the list of players placed on the DL in 2016. Pitchers represent 56% of players placed on the DL even though they only represent 48% of the MLB roster (assuming 12 pitchers on the roster). However, Left-handed relievers fall way down on the list at 3.9%. Some of this is explained by the lower number of left handed pitchers on the major league roster.
But how does this year compare to other years?
The next table represents all Placements on the DL from 2009-2015 (7 previous seasons):
We find that the percentages of Pitchers placed on the DL in 2016 are very similar but with a 3.8% increase compared to previous year’s averages (2009-2015).
We find that the percentages of Pitchers placed on the DL in 2016 are very similar but with a 3.8% increase compared to previous year’s averages (2009-2015).
In calculating the statistics on this, we find that the difference is not statistically significant with a p value = .53. So there is no significant change in the percentage of pitchers on the DL in 2016 compared to position players. Of course this does not mean that the number of DL pitchers has not increased. It has! This indicates that the new record of 561 players placed on the DL is not caused solely by an increase in injured pitchers but rather it due to increases in players of all positions.
DL Days by Position
Moving on to the amount of DL Days lost by position, we are going to first breakdown positions by DL Days lost similar to what we did with placements. We added a new metric that I call Severity Index Number (SIN). This is simply how long a player takes to recover from an injury once he is placed on the DL. In this case we will not be looking at specific diagnosis but rather how long it takes a pitcher or a player to recover from any injury. Eventually we will cover that but right now we will stay in the category of a player’s position.
This is a table of DL Days in 2016. This is similar to the table that we did with Placements.
As expected, the ranking of the positions is very similar to the placements. Now we will condense the pitcher’s numbers:
We see that percentage of DL Days at 63% is higher than the 56% that we show with Placements. Let’s see if this has changed from the data from the previous 7 seasons.
These tables indicate that there was no change in the percentage of DL Days lost to pitchers between the two cohorts (2016 vs Average of 2009-2015).
Severity Index
In working with DL data over the years, I saw some teams that had low DL placements that resulted in high DL days lost and some had the reverse; high DL placements but low DL Days lost. It seems that some teams had more “severe” injuries that required a longer healing and rehab time than other injuries. By using a simple calculation, this can be captured in one number that I call the Severity Index Number or SIN.
Severity Index Number = Total Number of DL Days/DL Placements
You can look not only at a particular team but the entire league over a period of time. This is demonstrated in the following table and chart, examining SIN from 1998-2015.
The chart indicates that the Severity Index Number is pretty stable with no increase or decrease over the past 18 seasons in spite of increases in the number of placements over the same period.
This trend line that has a p value = .64 and a R2 of .01 indicating the changes are not statistically significant.
So how does 2016 stack up against the previous 18 seasons on SIN? As you can see, there is only a small insignificant change from the previous 18-year average.
Two points that need be summarized here is that there has been no increase in the severity of injuries and the average of 55 days is below the 60-day DL requirements. The average player’s injury does not take over 60 days to recover and therefore does not necessitate transfer to the 60-Day DL.
Let’s examine the differences between the Severity Index between Pitchers versus Position Players. From the tables below, it is not surprising that Pitchers spend more time on the DL per injury than position players. Some of this may be due to the fact that it typically takes more time to rehab and conditioning a pitcher, especially a starting pitchers, than a position player. This is reflected in the fact that MLB allows a pitcher to have 30 days to rehab in minor league games as opposed to position players who only get 20 days.
Here is the table of all the teams in 2016. I usually do not like to list DL statistics by team because some people think a higher or lower number with some variables are a reflection on the quality of the medical team. In future blogs we will look at the multiple variables that go into players on the DL and the potential causes of injuries in baseball. But here is the 2016 by SI and Team:
This shows a large range in SIN of 31.6 to 89.1. The Standard Deviation is 14.4.
Conclusion
Unfortunately, the numbers related to DL has gone up compared to what was a record year in 2015. DL Placements (561) and DL Days (31,662) have eclipsed the short-lived record of 2015 as was shown in Part 1 of the analysis of the 2016 DL. In this portion of the analysis we looked specifically at injuries by positions. Although the total DL Placements rose, we did not see one position group reflect a significant change. It appears that the increase in injuries occurred over all position and not just pitchers as one might assume.
We also introduced a new injury metric, Severity Index Number (SIN). This number reflects how long a player remains on the DL and overall indicates the severity of the injury he incurred. Although the Severity Index has remained constant over the past 19 seasons, it does vary greatly from team to team. Not surprisingly, pitchers have a higher Severity Index compared to position players (63.7 days versus 47.2 days).
Conclusion
Unfortunately, the numbers related to DL has gone up compared to what was a record year in 2015. DL Placements (561) and DL Days (31,662) have eclipsed the short-lived record of 2015 as was shown in Part 1 of the analysis of the 2016 DL. In this portion of the analysis we looked specifically at injuries by positions. Although the total DL Placements rose, we did not see one position group reflect a significant change. It appears that the increase in injuries occurred over all position and not just pitchers as one might assume.
We also introduced a new injury metric, Severity Index Number (SIN). This number reflects how long a player remains on the DL and overall indicates the severity of the injury he incurred. Although the Severity Index has remained constant over the past 19 seasons, it does vary greatly from team to team. Not surprisingly, pitchers have a higher Severity Index compared to position players (63.7 days versus 47.2 days).
1 Comment
2/21/2019 06:04:35 am
I had a hard time understanding the article because its all about analytics! I am the type of person who hates seeing numbers and this is never a delighting experience for me. Perhaps, I need to make a research first and educate myself with the stuff before reading an article I know nothing about. This is a lesson-learned for me! If you aren't familiar yet with the topic, you are always free to make a research out of it!
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