The Bengals have a contract deal with one of their promising defensive ends and set in motion another becoming one of the top free agents in next year’s class.

On Monday, Carlos Dunlap agreed to be a Bengal through the 2018 season. He signed a six-year contract worth $40 million. The team announced the deal Tuesday.

“One of our key offseason goals was to continue signing and extending our key players, and the signing of Carlos is another positive step,” said head coach Marvin Lewis. “Over his three seasons with us, Carlos has continued to progress and develop. He has demonstrated the ability to be productive as a three-down player, and we are glad to have him committed to be a part of our future.”

According to Pro Football Talk, Dunlap will earn $18.7 million before the start of next year’s training camp and $20 million total during the 2013 and ’14 seasons. Dunlap, who is entering his fourth season, was going into the final year of his rookie deal and had a cap number of $1.489 million.

Drafted in the second round in 2010, Dunlap has been consistently rated among the top pass rushers in the league. According to Pro Football Focus, Dunlap had 49 pressures in 363 pass rushing snaps off the left side last season. In three years, he has 20 sacks, including 6.0 last season. He also has scored two touchdowns in his career, including one last year off an interception in the regular-season finale against Baltimore.

While Dunlap is a talented play-maker who matured a great deal last season, one of the biggest keys for him will be remaining healthy. He has yet to play all 16 games and has missed significant portions of the preseason all three years.

Last year, Dunlap suffered a knee injury in the preseason opener against the Jets which kept him out until Week 3 at Washington.

Not only have the fans been waiting for Dunlap to have a breakout season but Marvin Lewis and the coaching staff have as well. Dunlap was listed as the starter at left end all last year but Robert Geathers saw the first snap in every game. Dunlap though averaged 45.2 snaps per game to Geathers’ 40.4.

With the defensive line being the team’s biggest strength, they had 42 of the team-record 51 sacks last season, the Bengals have done well in retaining their guys. Before the start of free agency four months ago, they re-signed Geathers and Wallace Gilberry.

Said Dunlap of the defensive line during offseason workouts: “The camaraderie is already there. Now we just have to get better together. We know how all of us play. We’ve played together for a couple of years now, so it should be more natural.”