Six months after Miami Dolphins coach Joe Philbin wavered on Ryan Tannehill as his starting quarterback, the organization gave Tannehill a four-year extension averaging $19.25 million per season. That is the NFL's sixth-highest average.

Tannehill's new contract carries $21.5 million guaranteed in full and another $23.5 million guaranteed against injury. What sounds excessive for a player with modest credentials is very much in line with the NFL market for quarterbacks. "I think both sides won on this deal," a contract negotiator for another team said, echoing what others in the industry are saying.

Is the NFL out of its mind when it comes to quarterback valuation? The Dolphins' deal with Tannehill provides an opportunity to re-examine the pricing of the position. What is an average (or slightly above-average) quarterback worth? Is the fear of not having a viable quarterback driving the market out of control? Insights from agents and team contract negotiators provide a deeper level of understanding while setting expectations for the next wave of quarterback signings.

Six things to know about QB contracts

1. Luck, Newton and Wilson represent the next frontier.

Agents and negotiators expect Andrew Luck to command up to $25 million per year on his new deal, and without much drama. They are more curious to see what happens with Cam Newton and Russell Wilson. Both should wind up earning at least $20 million a year, these insiders thought.