San Francisco 49ers linebacker Chris Borland has retired from the NFL after just one season.
The 24-year-old was selected in the third round of the 2014 Draft by the 49ers, and he enjoyed a successful campaign in the heart of the NFC West side's defense.
However, Borland has decided to end his career due to fears over his long-term health in the area of concussions and resulting head trauma.
"I just honestly want to do what's best for my health," Borland told ESPN. "From what I've researched and what I've experienced, I don't think it's worth the risk."
49ers general manager Trent Baalke said in a statement: "While unexpected, we certainly respect Chris's decision. From speaking with Chris, it was evident that he had put a great deal of thought into this decision. He was a consummate professional from day one and a very well respected member of our team and community.
"Chris is a determined young man that overcame long odds in his journey to the NFL and we are confident he will use the same approach to become very successful in his future endeavours. We will always consider him a 49er and wish him all the best."
Borland joins fellow 49ers linebacker Patrick Willis to retire from the league in the past week.
