Concussions are such a big issue in the NFL that players are retiring due to fear of getting one. The latest is Kansas City Chiefs safety Husain Abdullah, who announced on Monday that he is retiring.

Abdullah cited numerous reasons for his decision to retire, but the primary reason is his health, as he has had five concussions in his seven-year career, according to ESPN. He suffered the fifth concussion last year.

“I would like to thank the Minnesota Vikings for giving me an opportunity to make the team after going undrafted in 2008,” Abdullah wrote on Instagram. “I experienced a great deal of growth both as a football player and as a person during my 4 years in Minnesota. Thank you. The Kansas City Chiefs will forever have a special place in my heart. After sitting out of football to fulfill my Hajj Pilgrimage in 2012, the Chiefs were the first to call. The three years I spent playing for KC may have been the most enjoyable football experience in my entire life. Thank you. Sitting for five weeks last year after suffering the fifth concussion of my career, I had a lot to contemplate. My goals moving forward are to be of benefit to my family, my community, my country and hopefully the world. Having a sound mind will be vital in accomplishing these goals.”

Abdullah signed with the Vikings in 2008. He spent four years with the team before signing with the Chiefs. He had 104 tackles, two interceptions and 15 pass deflections with the Chiefs, according to the Kansas City Star. Abdullah had 203 tackles, six interceptions and two touchdowns overall in his seven-year career.

With Abdullah retiring, the Chiefs have Eric Berry, Ron Parker and Daniel Sorensen as safeties. They have moved cornerback Jamell Fleming to safety and have signed Jordan Kovacks and Tyvon Branch.