The 25-year-old has had an excellent start to the season, recording more receiving yards and touchdowns inside four games than he did in the entire 2013 campaign.
Fangio feels that Quick's developement is there for all to see, and has ensured that his defenders are fully aware of the threat that he poses them.
"Well, he's a size receiver, number one. He's got 4.5 speed. And to me, he's just playing with a lot more confidence and knowledge of the game," Fangio told reporters.
"Just playing with more confidence, more aggressiveness. Going to get the ball and he's feeling comfortable knowing the routes he's running, being in the same system now since he's been there."
The 49ers face off against the Rams in their NFC West showdown on Monday.