49ers' Chris Borland, 24, quits NFL over concussion worries
49ers' Aldon Smith prepares for post-suspension return, Sports
Chargers lead 49ers 7-0 after 1st quarter - The San Diego Union-Tribune
Patrick Willis Injury: Sprained Ankle For 49ers LB Isn't Serious
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49ers lose LB Willis for season
NFL: 49ers' Willis to undergo season-ending surgery
Patrick Willis out for season
San Francisco 49ers linebacker Chris Borland retiring after rookie season because of concussion concerns