IRVING, Texas -- Linebacker Sean Lee will be with the Dallas Cowboys through 2019.

Lee signed a six-year extension Wednesday worth as much as $51 million, including a $10 million signing bonus, according to a source. The base value of the deal is $42 million. He will make a $630,000 base salary in 2013, and will have base salaries of $5.5 million (2014), $2.5 million ('15) and $3 million ('16), with $7 million base salaries from 2017 to '19.

With 80 percent play time during the next two years, Lee can earn an extra $1.5 million on his 2015 base salary that is guaranteed. From 2016 to '19, he can earn an extra $7.5 million toward his base salaries with 80 percent play time in the previous years.

"I'm extremely excited. I was blessed to be able to be drafted by a great franchise," Lee said in a video interview posted on the team's website. "To have an opportunity to be here a long time and hopefully compete for a Super Bowl is fantastic."

Lee, a second-round pick in 2010, is poised to become the Cowboys' defensive version of tight end Jason Witten. Coach Jason Garrett has called Lee the "bell cow" on defense as a leader and, when healthy, one of the most productive defensive players in the NFL. Lee's approach, work ethic and love of football is the same as that of Witten, an eight-time Pro Bowler and the Cowboys' all-time leading receiver.

Lee, 27, has yet to play a full season and was limited to only six games last year because of a toe injury. He still managed to finish fourth on the team in tackles with 77. He also had eight quarterback pressures, an interception and a forced fumble.

Lee missed one game in 2011 because of a partially dislocated wrist, playing most of the season with a protective cast that covered his entire hand. He also missed two games in 2010 because of a hamstring strain.

Without being specific, Lee said his new contract takes injuries into account.

"I've said I need to find a way to stay on this field, and the contract is extremely fair, where if I'm on the field the whole year I'll be able to get paid," Lee said.

"At the same point, if I do have injuries, it protects the Cowboys, and I think that's fantastic, especially with the injuries I've dealt with in the past."

Lee is one of only two active linebackers to have recorded interceptions of Peyton Manning and Tom Brady.

Information from The Associated Press was used in this report.