Vikings receiver Stefon Diggs has speed to burn, but can he sustain it?

Spielman might want to take a close look at the data for one of his players whose speed is his primary weapon: receiver Stefon Diggs.

Diggs had 849 yards and eight touchdowns last season and earned himself a five-year, $72 million extension thanks to his speed.

"His explosion when he is next to a defender, it's uncommon," Vikings receivers coach Darrell Hazell said. "His ability to create separation in a 3-yard box is what makes him really special. When he gets on the hip of a guy, the distance that he creates in a split second is what makes him very unique."

The memory of Diggs racing down the sidelines to beat the Saints and help the Vikings advance to the NFC Championship Game is a memory forever etched in the mind of Minnesota sports fans.

Just before reaching the end zone on that play, Diggs reached a maximum speed of 18.6 miles per hour, according to the data company Sportradar. That kind of speed, however, was rare for Diggs in the latter quarter of the season.

Sportradar's data includes the maximum speed and the average speed for every play that Diggs was targeted in the regular season and postseason, a total of 117 plays. In Weeks 1-4 last season, Diggs had an average speed of 10.3 miles per hour, which tied for 10th fastest among receivers in the NFL. He had 391 receiving yards over those four weeks.

But during Weeks 14-17, Diggs had an average speed of 8.5 mph — 48th among receivers — and had just 219 receiving yards. (By comparison, Adam Thielen was consistent from beginning to end, averaging close to 9.3 mph in the first and last four weeks of the regular season.)

It'd be easy to blame this decrease on the groin injury that kept Diggs out for two games (Weeks 6-7), but upon his return Diggs posted some of his highest speeds in Weeks 8, 10 and 11, when he averaged between 10.1 and 10.9 mph, in line with his early-season numbers.

Then it dipped, and Diggs hit his nadir in Week 14 against the Panthers, when he had an average speed of just 6.6 miles per hour and an average maximum speed of 10.9.

To Hazell, it's hard to pin that decrease on just one issue. One thing he said the coaching staff has had to do is to manage Diggs' enthusiasm before and in the early portion of games.

"Obviously, he's one of the 'A' players, but it's very important that you manage that throughout the course of the week," Hazell said. "He's a very excitable guy and energetic guy, so he's got to make sure, and we talked with him about this all the time, making sure he controls the emotions before the game so his tank doesn't get empty.

"His speed is one of his top three elements that makes him special and different."

Hazell said Diggs' fast-twitch muscle fiber is uncommon, even in the NFL. That fiber, which enables Diggs to perform in powerful bursts, is what allows him to create separation and maintain that speed down the field.

"It gives you space to make the play on the ball, and it also allows you to run after the catch," Hazell said. "It's not just a catch and the collision that allows you to advance the football. That's what he was really good at with some of those catches."

When Diggs is healthy and humming, few can stop him. His challenge now is to stay healthy for an entire season — and maintain his peak speeds at all times.

Chris Hine is the writer for North Score, the Star Tribune's sports analytics beat: startribune.com/northscore. E-mail: chris.hine@startribune.com