Bye Week Blues: Do Bye Weeks Affect Team Injuries?

Picture this: You’re a starting player on the Texans’ defense.

The off-season was tumultuous to say the least: Your starting quarterback, Deshaun Watson, was replaced by a journeyman in Tyrod Taylor, your rookie head coach, David Culley, has been a wide receivers coach for his 27 years in the NFL, and your executive vice president of football operations, Jack Easterby, is widely known as the NFL equivalent of Rasputin.

You play the Colts and Texans two times each, and will be asked to tackle 6’3″, 238 pound running back Derrick Henry, and 5’11” 227 pound running back Jonathan Taylor, who both had top speeds of 21.62 and 21.6 miles per hour in 2020. That week 10 bye can’t come soon enough.

Season after season, fans and pundits alike harp on the bye weeks assigned to teams, concerned that week 4 byes are too early, and cause teams to tire out over the final stretch of the season heading into the playoffs, yet week 12 byes are too late, and can cause teams to burn out earlier.

So naturally you’d think to yourself that the middle of the season, around week 8 must be the sweet spot for a giving a team a chance to heal and recover.

But does the data back that up?

Looking at seasons from 2009 to 2020, bye weeks were normally held during week 4 and week 12, with a few exceptions. The first exception being week 1 in the 2017 season, where the Bucs and Dolphins had their opening game postponed due to Hurricane Irma, and their bye week moved to week 1 as a result. The other exceptions being week 13 used as a bye week for the Browns and Titans in the 2016 season, and for the Bucs and Panthers in the 2020 season.

To the NFL’s credit, they do a good job of scheduling as many byes as possible as they can in the middle of the season, with byes during week 8 and week 9 occurring most frequently during those 12 seasons. The other bye weeks are all fairly frequent, with the exception of Week 4, which only occurred 7.81% of the time.

Using nflfastR for the injury data source, I was able to use Python to compile the total injury status designations for all 32 teams from 2009-2020, and match them with their byes for their respective seasons.

The above tables represent the average total injury designations per each bye week, which is calculated by dividing the total injury designations for a particular bye week by the amount of times the bye week occurred. For example, for the two teams that had the week 1 bye in 2017, they had a combined total of 203 injury designations, and since a week 1 bye has only occurred twice (for both teams in that 2017 season), the average total injury designations would be half of the total, giving an average of 101.5 total injury designations for teams that had seasons with week 1 byes.

The total injury designations include every player that was designated as questionable, probable, doubtful or out for a given game. The NFL decided to drop the probable injury designation prior to the 2016 season, and the table on the right reflects the average total injury designations excluding probable designations.

Excluding week 1 and 13 from the data due to only 6 bye weeks occurring during those weeks, there doesn’t seem to be any correlation between a team’s bye week and injury designations.

Based on the assumption that the closer to the middle of the season that a team’s bye occurs, the lower amount of injuries a team will experience, we would expect the shape of the graph to be an inverted bell curve. While teams with week 4 byes did have the second highest number of injury designations on average, and a decrease in injuries occurs for the next 2 consecutive weeks, with a large drop-off in designations from week 5 to week 6, the number of injury designations shoots back up as the middle of the season approaches with week 7.

The middle of the season is fairly consistent from weeks 7-9, and then spikes up a decent amount for week 10, before experiencing another large drop-off from week 10 to week 11, and another smaller drop-off from week 11 to week 12.

Teams with a week 12 bye had the least amount of injuries at 98 injury designations on average, however the sample size is very small as a week 12 bye only occurred 3.12% over the past 12 seasons.

There are many factors that go into a team’s injuries for a given season, whether it be poor conditioning, giving players an unsustainable volume of touches (such as Derrick Henry and Christian McCaffrey in the 2021 season), inadequate playing field surfaces, and perhaps the biggest factor of all – randomness/chance.

Bye weeks are definitely important in giving a team a mental break to recharge and refocus, but with respect to the media’s claims that a bye week being scheduled during a certain part of the season would help keep a team healthy, the evidence just isn’t there to support it.

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