A former NFL player, whose memory has begun to slip away after years of concussions suffered while he was playing in the league, has penned a heartbreaking book that is a love letter to his wife and four daughters.

Ben Utecht, who won a Super Bowl ring playing tight end for the Indianapolis Colts in 2006, released Counting the Days While My Mind Slips Away on Tuesday.

The book is a way for him to preserve the memories he still has in the event they should slip away after the five major concussions he suffered during his career - not to mention the countless un-diagnosed micro-concussions.

They have already caused him to forget some major moments.

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Memories: Ben Utecht, 35, has written a book for his wife and four daughters entitled Counting the Days While My Mind Slips Away (above with his four daughters Elleora, Amy, Joan and Katriel)

The former NFL tight end wrote the book as he begins to experience memory loss following a career in which he suffered five concussions (above during the 2006-7 season wih the Colts)

'I try to value every moment, no matter how small. Until recently, I never realized how special memory is,' Utecht said in a recent interview with Sports Illustrated.

'This book is a keepsake. I wanted to provide content for my daughters to be able to hold on to, to have forever.'

The book also details the fifth concussion Utecht suffered during his career back in August 2009, when he was playing for the Cincinnati Bengals.

It was during training camp that Utecht, then 29, took a full speed hit from linebacker Darryl Blackstock that left him unconscious on the field for 10 minutes.

He was placed on the injured reserve a few weeks later when his symptoms continued to persist, and then unceremoniously dumped by the Bengals that November.

After the injury, Utecht experienced common side effects of brain injuries, such as amnesia, dizziness and sudden mood changes. According to him, when his oldest daughter told a family doctor that she was sometimes afraid of her father, it 'broke his heart' and he had 'a wake-up call.'

'To really think about a time where I may wake up someday and not recognize the person that I’ve been lying next to for the last 30 years, yeah, that’s scary,' he told the Minneapolis Star Tribune.

'I think every person would fear something like that.'

Utecht then began his work as an activist - increasing public awareness of issues related to brain injuries and concussions. Recently, he was named a national spokesperson for the American Academy of Neurology and the American Brain Foundation.

He also filed a grievance suit against the team when they refused to pay out his salary for the season which he eventually won - three years after leaving the game.

Tome: Utecht's final concussion in 2009 effectively ended his career and shortly after he began forgetting events, like a good friend's wedding (book above)

Love: Utech and his wife Karyn (above) in a music video he filmed

Utecht released a statement at that time saying: 'In 2009 my NFL career was promising, but it ended suddenly with a brain injury. Three years later my family and I have closure with the successful conclusion of my contract dispute.

'We are grateful for the support we have received from all of our friends in professional football and beyond. I will continue to help the NFL in any way I can to educate people about brain safety and the seriousness of this issue.'

By then he had begun to experience the impact of those concussions, at first forgetting small things and then forgetting the wedding of one of his best friends.

Utecht was even one of the groomsmen at the event.

'It's the most awful feeling, not knowing what else might slip away, too,' he told Sports Illustrated.