After Patrick Willis' retirement last Tuesday, 24 year old Chris Borland figured to lead the San Francisco defense for at least the next few seasons. Instead, Borland stunned the sporting world by retiring over the long term effects of repetitive head trauma. 

Borland becomes the highest profile player to retire over these concerns. He amassed 107 tackles in just 14 games and 8 starts as a rookie last season. His immediate success drew plaudits from writers like Bill Barnwell, who deemed him the "patron saint of the Grantland podcast" and the defensive rookie of the year through Week 13. In Weeks 9 and 10, Borland recorded 35 tackles against the St. Louis Rams and New York Giants, the highest two-game mark for any player this decade. 

Instead, he ended his career as abruptly as it took off. Borland "thought about what I could accomplish in football, but for me, personally, when you read about Mike Webster and Dave Duerson and Ray Easterling, you read all these stories, and to be the type of player I want to be in football, I think I'd have to take on some risks that, as a person, I don't want to take on." 

Duerson and Easterling were diagnosed with a devastating brain disease, chronic traumatic encephalopathy or CTE, after their deaths. Both committed suicide, so the former 49er inside linebacker did not want to join that list. 

This story will surely dominate the national news circuit in the days and weeks to come. The San Francisco 49ers suffered another catastrophic blow in this nightmarish offseason, but that is merely a footnote to the greater debate about player safety that will surely erupt.