The one-year tag will be worth in the neighborhood of $10 million, which was the average of the five highest-paid linebackers from the 2010 season.
Harris has teamed with cornerback Darrelle Revis to make up the heart of Rex Ryan's defense. Harris, who made a base salary of $550,000 in the final year of his rookie deal, was voted the Jets' MVP by his teammates after having 99 tackles and three sacks in his fourth season.
Since being a second-round pick out of Michigan in 2007, Harris has 428 tackles, 15 sacks, five forced fumbles and two interceptions.
General manager Mike Tannenbaum said shortly after New York's AFC Championship Game loss to the Pittsburgh Steelers that re-signing Harris was a priority. The Jets still could lock him up to a long-term deal once the NFL's uncertain labor situation is cleared up despite placing the franchise tag on him.
Harris is the last of the team's "Core Four" players -- including Revis, Nick Mangold and D'Brickashaw Ferguson -- to sign a new contract. The other three players were given new deals before the season, and Harris acknowledged in August that he wouldn't get his until after this season because of constraints due to the collective bargaining agreement.
The league has advised teams that they have until Thursday to tag players.