MANKATO, Minn. -- Perhaps the best tool at Minnesota Vikings coach Mike Zimmer's disposal, as he tries to spur the Vikings' offensive line to improvement in 2015, is a wave of defensive linemen Zimmer can turn loose in different combinations during training camp.

The Vikings got back to work on Friday after a day off, and their practice was marked by a series of one-on-one pass-rushing drills designed to pit players against a series of different opponents. Zimmer said the matchups were somewhat scripted, but the Vikings run through enough permutations in the rapid-fire drill that most linemen get a chance to face each other at some point.

"I'm trying to get different matchups, so I don't have to put the whole second group against the whole first group," Zimmer said. "I can see some of these younger guys against the older guys, and vice versa. It's really about trying to get some evaluations of different people."

Rookie Danielle Hunter was among the stars of the one-on-one drills Friday, as he got the better of Matt Kalil and used his speed to wheel around T.J. Clemmings. Hunter only had 1 1/2 sacks at LSU last season, but Zimmer said the 20-year-old already has shown a better understanding of the rush angles he needs to beat offensive tackles.

"We're just trying to find roles for guys right now," Zimmer said. "What can this guy do; how can he help us?"

Here are some other notes from Friday's practice:

• Play of the day: Wide receiver Stefon Diggs is drawing attention in Mankato with a series of impressive catches, and he made two on Friday, going low for a ball before leaping to catch a Shaun Hill pass in the end zone. Hill raised his arms as the catch drew a round of "Ooohs" from the crowd.

• Shift at safety: The Vikings still are trying to solidify the safety spot next to Harrison Smith, and they shifted some players around on Friday afternoon, giving Antone Exum some first-team work next to Smith in an early drill. It's early in the Vikings' safety competition, but it's worth noting the team likely will begin to move a few players around, after keeping the status quo and using Robert Blanton with the first-team defense during the first four days of practice.

• McKinnon moving around: The Vikings lined up running back Jerick McKinnon at wide receiver on Friday, which Zimmer said was to give the second-year back some time to pay extra attention to his route-running. He also took on several linebackers in pass-rushing drills. "He had some good ones, and he had some bad ones," Zimmer said. "He got beat a couple times, and he won a couple times, which is typical. It's the first time we've done it. We need to do that more."

• Harris leaves early: Running back DuJuan Harris left the practice field with a trainer early on Friday, but didn't appear to be limping, and Zimmer didn't show much concern about the injury.