Robert Griffin III learned an important lesson about never wearing Adidas

The NFL has slapped Washington Redskins quarterback Robert Griffin III with a $10,000 fine for wearing an Adidas jacket and t-shirt to a postgame news conference last Sunday. Though Griffin has a private endorsement deal with Adidas, Nike is the National Football League's official clothing maker. $10,000 is no laughing matter, but considering that the Redskins rookie has a four-year, $21 million contract with his team, we're guessing can probably spare a few grand for wearing "unauthorized apparel."

This isn't the first time Griffin has neglected to honor the league's agreement with Nike. According to NBC Sports, Griffin covered up his Nike swoosh on his pregame attire earlier this year -- but got off with just a warning.