The San Francisco 49ers saw some players take the next step in their careers in 2013. Let's look at the top three players who enjoyed breakout seasons:1. Tramaine Brock: Brock had a stunning ascent in 2013. He went from being a special teamer in training camp to finishing the season as the 49ers' top cornerback. It earned him a four-year contract extension. He has a place as a starter for the long term.2. Glenn Dorsey: This worked out great for the 49ers.