There is no official rating system for NFL players.
Whether one is overrated or underrated depends upon who is doing the rating.
The ones ESPN's John Clayton placed on his all-underrated team were generally not early draft choices. They had not been to Pro Bowls. They were sometimes overshadowed by higher-profile teammates. And, in 11 of 22 instances, those players came from teams with divisional affiliations in the West.
My quick thoughts on the five players Clayton chose from the NFC West:
Steve Breaston, WR, Arizona Cardinals. Breaston finished last season with a career-high 15.3-yard average, but his reception totals have retreated each year since his 1,000-yard season in 2008. The trend continued last season even with Breaston becoming a full-time starter following Anquan Boldin's departure. Injuries and quarterback play have been key variables. Breaston's value goes beyond his receiving stats. See: Week 1 last season.
David Hawthorne, LB, Seahawks. Hawthorne could have appeared on an underrated list before now. He has vastly outperformed initial expectations through aggressive play. Hawthorne has 27 starts, nine passes defensed and four interceptions over the past two seasons. Football Outsiders knocked him down for allowing 10 broken tackles last season.
Dashon Goldson, FS, San Francisco 49ers. Those following the 49ers closely expected more from Goldson last season. That does not mean Goldson performed horribly, however. He was generally solid, but did not take the next step. Goldson has three sacks, 11 passes defensed and five interceptions in two seasons as a starter. He scored on a 39-yard interception return last season.
The chart breaks down Clayton's selections by division and position.