It's well-known that the Denver Broncos have Tim Tebow and Adam Weber as the only quarterbacks under contract for the 2012 season at the moment. John Elway has publicly told the media that Tebow is the starter entering training camp but that there will be an actual competition for the spot. So, the Broncos will look into signing a quarterback during free agency or at the 2012 NFL Draft.
If we look at the former option, the Denver Post's Mike Klis offers some names for the position:
That really doesn't seem like a list of players that could come in and provide an honest competition for Tebow. Redman has some starting experience but is the definition of a pure backup quarterback. Hill has started for the San Francisco 49ers and the Detroit Lions and could conceivably provide a bit of competition. Henne just got injured while I wrote this (it's a joke, people!). Young is the "name" player here because he was once the No. 3 overall pick, and comparing him and Tebow has happened over the last few months. Carr has gone from No. 1 overall pick in 2002 to Eli Manning's backup in recent years. Anonymity in Denver available as well.
This is a list of players that wouldn't provide serious trouble to Tebow for the starting spot -- unless he struggles through camp.