Former NFL players Zach Thomas and Kyle Turley must have the organ donor sticker on their driver’s licenses.

According to The New York Times, both retired players will donate their brain and spinal cord tissue for concussion research. Thomas and Hurley also plan to help the Center for Study of Traumatic Encephalopathy at the Boston University School of Medicine.

The NFL and the NFLPA said they would support the center and encourage players to participate in the study. The research will help scientists understand the long-term impact of sports-related concussions.

"The only way we will truly understand the long-term effects of repetitive head trauma in football is to study a large group of athletes throughout their lives and then examine their brains following death," Center co-director Dr. Robert Stern told the Times.

Concussions have been a hot topic in the NFL. Ben Roethlisberger and Kurt Warner were two of the biggest names to suffer concussions this season.

The league issued new guidelines on managing concussions less than two months ago. The rule has challenged the NFL and its players to change long-held attitudes regarding injuries.