The Vikings have locked up one of the NFL's best safeties, Harrison Smith, who was slated to be an unrestricted free agent after the 2016 season.

The team announced this morning that Smith has signed a contract extension, which will keep him in Minnesota through the 2021 season.

"It's very hard to put into words right now," Smith told the team's website. "Coming into the league, getting an opportunity after getting drafted by [General Manager] Rick [Spielman] and being able to stay around here and just be a part of what we're building here, what Coach [Mike] Zimmer is building… It's huge in every type of way I can think of, being able to stay in this building and chase a championship."

According to a league source, it is a five-year extension worth $51.25 million with $28.578 million guaranteed. At $10.25 million per season, the new deal makes Smith the NFL's highest-paid safety, according to OverTheCap.com.

Smith was a first-round draft pick of the Vikings in 2012. Now is in his fifth season with the organization, the 27-year-old has thrived under Zimmer, who uses Smith in a variety of ways to put stress on offenses.

Smith made his first Pro Bowl in 2015, albeit as an injury replacement, after recording 66 tackles, 1.5 sacks and a pair of interceptions in 13 games. He returned one of those interceptions for a touchdown, giving him four career interceptions returned for a touchdown, a franchise record.

In his first four NFL seasons, he racked up 320 tackles, 5.5 sacks and a dozen interceptions. Willing to hit hard, he has also forced three career fumbles.

After the 2015 season, G.M. Rick Spielman expressed a desire to extend Smith's contract, playfully joking that he was one of the "better," not best, defensive playmakers in the NFL in the hopes of keeping his price down.

Smith, meanwhile, continued to express confidence a deal would get done.

The signing of Smith continues a trend for the Vikings, who under Spielman have aimed to get young players whom they feel are still ascending under contract before they reach free agency. Those players have included guard Brandon Fusco, tight end Kyle Rudolph and kicker Blair Walsh.

Smith now has gotten long-term financial security, but it seems unlikely that will change his mindset. Immediately after signing his new deal, Smith celebrated by walking down the hall to attend a team meeting.

"With the fans in Minneapolis, I couldn't imagine a better place to play and a better organization to be a part of," Smith told the team's website. "I just can't say enough about how blessed I am to stay here."