Seau, a 12-time Pro Bowl selection who played for 20 years in the NFL, was found unconscious by his girlfriend on Wednesday with a gunshot wound to the chest and a revolver nearby, police said. The former San Diego Chargers linebacker was 43.
"At this time, the Medical Examiner's Office is awaiting the family's decision regarding study of the brain for repetitive injury by researchers outside of the office," the San Diego County Medical Examiner's Office said.
The Seau family's pastor, Shawn Mitchell, a former chaplain for the Chargers, said Seau likely suffered concussions during his long football career.
"He would go in head-first," Mitchell said of Seau. He said a link between his career and death was something to consider because Seau played so long at such an "incredibly violent position" as linebacker.
He added, however, that Seau's family had not mentioned any concerns about recurrent head injuries contributing to the retired player's suicide at his beachfront home in Oceanside, just north of San Diego.
Seau's death came at a time of increased scrutiny of the effects of head injuries in football and the potential for such injuries to contribute to depression and long-term damage in professional players.
Over 1,500 former football players have sued the NFL over head injuries. On Thursday, 100 other retired players filed a lawsuit against the league on the same grounds in federal court in Atlanta.
The league disputes the claims in the suits, which accuse it of concealing links between football and brain injuries.
"Any allegation that the NFL intentionally sought to mislead players has no merit," Greg Aiello, a spokesman for the league, said in a statement.
"It stands in contrast to the league's actions to better protect players and advance the science and medical understanding of the management and treatment of concussions," Aiello said.
The league, in the face of criticism, has focused in recent seasons on health and safety issues. It has cracked down on hits to the head, and stiffened rules that prohibit players using their helmets as a weapon through head-first contact, which is subject to fines and suspension for repeat offenders.
Seau's death was at least the third suicide by a former NFL player since February 2011, when former Chicago Bears defensive back Dave Duerson killed himself and left a note asking that his brain be studied. Less than a month ago, former Atlanta Falcons safety Ray Easterling shot himself to death at age 62.
Easterling, a plaintiff in one of the suits against the NFL, had been diagnosed with dementia, and his wife said after his death that she wanted the league to "take responsibility."
Seau, who played for the Miami Dolphins and New England Patriots after leaving the Chargers, r etired after the 2009 season.