"Underrated" is an adjective that gets thrown around a lot when we talk about sports, but it can mean a lot of things. Sometimes, an underrated player is a quality player who isn't well known. Other times, it means a player who most fans think is good but who is really great. When the staff of Football Outsiders went through the league to find an underrated player from each team, we ended up with a mix of both.

Here's a look at some players we think should be better known and/or given more credit for their teams' success (or perhaps less blame for their teams' failure). Football Outsiders' advanced metrics are explained here. Pass-coverage statistics (which are adjusted for the quality of receivers being covered), blown blocks and player hurries come from Sports Information Solutions' game charting.

AFC East | AFC North | AFC South | AFC West

NFC East | NFC North | NFC South | NFC West

AFC EAST

Cornerback Stephon Gilmore

Gilmore was overshadowed last season by rookie Ronald Darby at cornerback but had a fine campaign in his own right, with a 50 percent success rate and 7.2 yards allowed per target in coverage (ranking 47th and 25th in those categories out of 75 qualifying cornerbacks), before suffering a shoulder injury in Week 13. Imagine how good Darby and Gilmore will be if Rex Ryan can remember how to reignite the Bills' pass rush.

Safety Michael Thomas

The Dolphins underrate their own players. If you are a role player who develops within the organization, the Dolphins are likely to let you leave via free agency so that they can spend more money on famous people. So without Olivier Vernon, Rishard Matthews or Lamar Miller to praise anymore, let's single out Thomas, an exceptional special-teams player (10 tackles and four assists last season) who also grew into a role as a solid nickel-package safety.