With football season just around the corner, it’s time to make sure your lucky jersey still fits, draft your fantasy team ... and think a little harder about the impact that the game can have on the brain.

Hate to be a buzzkill. But we can’t ignore this recently released study, which suggests that even a single season of concussion-free football can damage the brain.

Researchers took a look at the hits that 38 players on on a Division III college team took over the course of three seasons. By attaching an accelerometer to each player’s helmet, the scientists were able to capture every single blow the players were dealt, from the “small dings to hard slams.” Over the course of the study, the 38 players took collectively took a whopping 19,128 hits.

Of those, only two resulted in concussions, which we already know can have serious consequences on the human brain. But researchers did brain scans of the players before and after their seasons to figure out whether we need to be worried about those smaller dings, too.

Sorry. We probably do. When the scientists compared the pre-season scans to the post-season ones, they saw what they described as a decline, or a “kind of fraying” of the white matter tissue in the players’ midbrains.

You might know from watching the NFL that officials are trying to crack down on head-to-head hits, since those can often come with the impactful slam that can lead to a concussion or more serious injury. But somewhat surprisingly, the researchers found that the decline of the white matter in the players they studied was higher in the players that suffered more hits that twisted their heads, as opposed to head-on slams.

This suggests that those seemingly smaller hits, particularly the ones that cause a player to twist and set rotational forces into motion, could be damaging the brain in more ways than we knew.

Now, as always with the brain, we try to learn more. As much as we have figured out about this wildly important organ, it is still one of the most mysterious parts of our body.

We do know a little about the midbrain, the area where the scientists noticed a decline in white matter – it’s super important, as it helps to control a large part of the things you do with your eyes and ears, including visual processing, hearing and overall motor control. Damage to this part of the brain, even momentarily, can cause symptoms like ringing in the ears or issues focusing.

The doctor who led this study has also called it a potential “canary in a coal mine” for overall brain injuries. It can be incredibly difficult to nail down the root and location of brain injuries, but since damage to the white matter of the midbrain does show up on scans, it could alert brain experts that a patient’s entire brain is worth examining for further damage.

For this particular study, the doctors did not test the players on their motor skills or any processing abilities, so they’re not sure whether this fraying led to any long-term damage. But it’s a good base for further studies to learn more about the long-term effects of taking hit after hit on the football field – and a good reason to think twice before suiting up.