NFL teams have until Thursday at 4 p.m. EST to designate their unrestricted free agents as franchise or transition players, which gives them the right of compensation or first refusal.

The Eagles have been unable to reach a multi-year agreement with Trotter, forcing them to use the franchise player designation.

Franchise players must be tendered a one-year qualifying offer at the average of the top-five salaries at their position or a 20-percent salary increase, whichever is greater. But the original club can match any offer and retain the player, or receive two first-round draft choices as compensation if it decides not to match.

A two-time Pro Bowler, Trotter has led the Eagles in tackles each of the last three years. At 25 years of age, Trotter would have been a hot commodity on the free agent market if not restricted by the tag.

The average of the top five salaries for a linebacker is $5.5 million.

The Kansas City Chiefs will likely place a franchise designation on Gonzalez, a Pro Bowler each of the last three years, because the average salary of the top five tight ends is just $2.288 million.

The Seattle Seahawks are expected to designate Pro Bowl left tackle Walter Jones as a franchise player, although the average for offensive linemen is $4.92 million.

The St. Louis Rams may slap a tag on Fletcher, the team leader in tackles the last three seasons. However, that would require them to pay $5.5 million.

The Pittsburgh Steelers have never used either a franchise or transition designation on free agents, but are hoping to re-sign Pro Bowl linebacker Jason Gildon to a multi-year contract.

One of the NFL's premier pass rushers, Gildon led the Steelers with 12 sacks last season.

Steelers starting inside linebacker Earl Holmes is also eligible to become an unrestricted free agent in March, but will likely not receive a designation.

The Indianapolis Colts are considering putting a franchise tag on left tackle Tarik Glenn.

The New York Jets, who lost three starters -- tackle Ryan Young and cornerbacks Aaron Glenn and Marcus Coleman -- in Monday's expansion draft to ease their salary cap burden a bit are trying to re-sign free agent left tackle Jason Fabini to a multi-year deal.

If the Jets are unable to reach an agreement with Fabini by Thursday, they will designate him as a transition player. The transition average for offensive linemen is $4.442 million.

To designate a transition player, a club must offer a minimum of the average of the top-10 salaries at the player's position last season or a 20-percent salary increase, whichever is greater. A transition designation gives the Jets a first-refusal right to match an offer sheet given to Fabini by another club.

The free agency signing period begins on March 1.