Tramaine Brock was picked up as an undrafted free agent in 2010 by the San Francisco 49ers. He was released and resigned in a span of five days with the team, and over the course of the next three seasons, gradually saw an increase in play on the field, although most of it was on special teams.
In 2013, Brock caught his break, and never looked back. Inserted as a started thanks to injuries to the regular starters, Brock made his mark on a Sunday night nationally televised game against Houston, in which he intercepted a pair of passes, returning one for a touchdown.