MANKATO – Don't you dare take your eyes off Stefon Diggs.

If during the first week of Vikings training camp had you looked down at your phone to craft a clever tweet or turned to actually engage another onlooker in conversation, you ran the risk of missing another highlight from Diggs.

One moment he was crossing up the legs of a starting cornerback with a nifty whip route near the goal line. The next he was blowing by the secondary to catch a deep ball from quarterback Teddy Bridgewater. And, yes, that was him, too, making that one-handed grab in the back corner of the end zone.

"He's all over the place," wide receivers coach George Stewart said.

After Diggs came out of nowhere as a fifth-round rookie to lead the team with 52 catches and 720 receiving yards last season, the Vikings told Diggs to focus on learning all three wide receiver positions during the offseason.

With the addition of big-bodied split end Laquon Treadwell, the team's top draft pick, Diggs usually will line up off the line of scrimmage at the flanker position. But defenses will see the shifty 22-year-old in the slot, too, and occasionally at split end, the position he was forced to play as a rookie because of the presence of highly paid and underproductive flanker Mike Wallace.

Receiver Stefon Diggs during practice Friday.

"He was pigeonholed in one spot so we couldn't move him to take advantage of matchups," Stewart said. "That's why we preached position flexibility."

After a long afternoon practice in the sun Friday followed by self-imposed agility training designed to make him even quicker in and out of his breaks, then a several-minute scrum with reporters, Diggs didn't feel like going into the nuances of the flanker position as he made his way toward air conditioning.

"I haven't really been able to tell. I feel like I'm playing the same spot," Diggs said, later adding, "To me, it really doesn't matter where they line me up."

The obvious difference for Diggs is he will be positioned off the line, giving him a chance to evade press coverage and get a free release. Being off the line also enables the Vikings to put him in motion before the snap, forcing the secondary to scramble. Plus, Stewart added, the extra step will give him a fraction of a second longer to try to decipher the defensive scheme.

"He is a playmaker, and with playmakers like Randy Moss, Jerry Rice, Terrell Owens, Roddy White, you want to give them opportunities to make plays," said Stewart, who has coached them all. "And that's what he's doing."

In the 10 days since the Vikings first reported to Mankato, Diggs has been by far the most impressive offensive player, ahead of his quarterback and new left guard Alex Boone. He has looked a lot like the kid who last season became the first rookie in NFL history to rack up 85 or more receiving yards in his first four games.

His production tailed off, though. Diggs did not top 70 yards in any of the Vikings' final nine regular-season games, and he had 26 in their playoff loss.

Stewart chalked that up to the weather getting cold and All-Pro running back Adrian Peterson staying hot, leading the Vikings to throw the fewest passes in the league last season. He also noted that the Maryland product got more attention from defenses after his initial four-game explosion.

"I know fans and media think he slowed down in the second half," Stewart said. "He was very effective, and we expect him to continue where he left off."

Diggs, though, expressed disappointment with how his 2015 season ended.

"I feel like I'm better than what I showed," said Diggs, whose eyes often dart around during conversation, seemingly nonstop, the way he has darted around on the practice field. "But everything I did is in the past, and I look forward to a new year."

The Vikings are eager to see what the second-year receiver does for an encore, too. His routes seem sharper. His biceps and upper body look bigger. And his move to the flanker spot and occasionally the slot should benefit him.

Plus, Diggs has been producing so many big plays that on Friday he couldn't even remember the 70-yard bomb he caught from Bridgewater the day before, the one that left two defensive backs stumbling over each other as he pulled away.

Is it possible that Diggs has been scoring too many touchdowns in Mankato?

"Not too many touchdowns," he said with a smile. "Never too many of those."