Definition
To sacrifice someone, especially in an attempt to save oneself.
To remove or cast out someone or something out of one's protection, such as onto the streets, especially towards predators.
How People Actually Use It
To put someone, who is usually inexperienced, into a very difficult and extremely high-pressure situation where there is a high chance of failure.
"Throw to the wolves: An example would be making an 18-year-old kid who has never pitched in the Major Leagues, take the mound against the New York Yankees in Yankee Stadium in game 7 of the World Series, with the bases loaded in the bottom of the 9th with the Yankees down by one. Oh yeah, and Alex Rodriguez is at the plate. Have fun, kiddo, you've been thrown to the wolves."
Source: Urban Dictionary