Cowboys' Frederick Retires, Cites Play After Nerve Disorder – NBC
2016 Dallas Cowboys season - Wikipedia
Frederick back on the field
Cowboys Travis Frederick – Back From Autoimmune Disorder - ESPN
Cowboys All-Pro center Travis Frederick retires from NFL after 7
Guillain-Barre: What Cowboys' center Travis Frederick is going
Dallas Cowboys: Travis Frederick close to full recovery
What will Cowboys do to make room for David Irving? Terrance
Multiple Roles Must Be Replaced On The O-Line
Dallas Cowboys' Travis Frederick is battling rare auto-immune