Borland consulted with concussion experts and family members before announcing the decision . ' From what I ' ve researched and what I ' ve done , I do n't think it 's worth the risk , ' the 24-year - old said . He leaves the 49ers after an highly promising rookie season . A third round pick in last year 's draft , Borland ranks Patrick Willis , mark Worilds and Jake Locker as high - profile players in the past few days .
Borland spoke with concussion experts and family members before making the decision . 'From what I 've researched and what I 've experienced , I do n't think it 's worth the risk , ' the 24-year-old said . He leaves the 49ers after an highly promising rookie season . A third round pick in last year 's draft , Borland joins Patrick Willis , Jason Worilds and Jake Locker as high-profile retirements in the past few days .