Fourth-year Henderson signs extension through 2011

Fourth-year veteran E.J. Henderson, who has emerged as one of the league's top young weakside linebackers while playing in the "cover two" scheme installed by the Minnesota Vikings this season, on Friday signed a five-year contract extension.

The deal, which is worth a total of $25 million, includes $10 million in guaranteed bonuses. It will keep Henderson off the unrestricted free agent mark in the spring and ends speculation that the Vikings were not planning in investing heavily to retain the former University of Maryland standout.

The extension runs through the 2011 season.

A second-round choice in the 2003 draft, and the 40th prospect selected overall that year, Henderson came into the NFL regarded as a fairly one-dimensional defender. Because he spent most of his college career at middle linebacker, the position he manned in his first two NFL seasons, Henderson was viewed primarily as a two-down defender, tough versus the run but limited against the pass.

But in 2005, Henderson moved to weakside linebacker, starting 14 games there, and proved to the skeptics that he could operate well while playing in space.

Henderson, 26, has really blossomed, however, in 2006. In the "cover two" scheme implemented by first-year coordinator Mike Tomlin, he has become a standout playmaker. Henderson has recorded a team-high 108 tackles, along with three sacks, two interceptions, four passes defensed, one forced fumble and one fumble recovery, while starting all 13 games.

Minnesota has benefited from his breakout season, as the Vikings statistically rank fourth in the league in total defense and are No. 1 against the run.

Because the linebacker position is often undervalued by teams that use the "cover two" scheme, there was considerable speculation the Vikings might permit Henderson to test the free agent market in the spring of 2007. But the two sides negotiated for the past few weeks and discussions accelerated the last couple days.

For his career, Henderson has 358 tackles, five sacks, two interceptions and 13 passes defensed. He has appeared in 58 games and started in 41 of them.

The retention of Henderson means the Vikings have two veteran starting linebackers, Henderson and Ben Leber, secured for the long-term. Leber is signed through 2010. Starting middle linebacker Napoleon Harris is in the final year of his current contract and, without an extension, will be eligible for unrestricted free agency in the spring.

The team's first-round pick in this year's draft, linebacker Chad Greenway, is under contract through 2010. The former Iowa star has missed his entire rookie season, however, because of knee injury. The Vikings feel Greenway will be fully recovered for 2007 and anticipate him challenging for a starting job.

Len Pasquarelli covers the NFL for ESPN.com.