The Vikings have done a remarkable job building out a promising, young defense over the past few years and on Monday they locked up one of the key pieces to the unit by signing safety Harrison Smith to a contract extension.

The deal is a five-year contract and according to multiple reports worth $51.25 million with $28.578 million guaranteed with a $10 million signing bonus.

It's a very nice deal for Smith, who was under team control for a fifth year due to the Vikings exercising his fifth-year option. Minnesota should be thrilled about its ability to lock down one of the league's best players to a contract that will look very nice a few years from now.

In his four seasons with the Vikes, Smith has turned into a dynamic playmaker and an all-around excellent defender. He has recorded over 300 total tackles in his four seasons, is credited with 12 interceptions (and four touchdowns on those picks), 26 passes defensed, three forced fumbles and 5.5 sacks.

He's really elevated his game under defensive mastermind Mike Zimmer the last two years and is just 27 years old. NFL quarterbacks have a passer rating of 68.0 the last four years when targeting Smith per Pro Football Focus and a very tidy 43.3 rating in 2015, his best year to date.

He's in rarified air when it comes to statistical production.

When you start plugging this contract into the relative market for other players around the league, it's going to look like a top-shelf deal. Smith is resetting the market a bit, getting $10.25 million a year in total money, a hefty amount of guaranteed money ($28.578 million) and a decent amount of guaranteed money a year $5.7156 million.

But it's not an outrageous deal at all for a guy of his caliber, primarily because the safety market has such a low ceiling. Minnesota is smart to max out Smith now, give him the top deal on the market and then let the Chiefs (Eric Berry) and Seahawks (Earl Thomas) worry about paying more than the last guy.

Smith is still in his prime and is still establishing himself as one of the top safeties in the game. It's a lot of money but still a very good value for a critical piece to an emerging defense.