EDEN PRAIRIE, Minn. —The Vikings wrapped up what Head Coach Mike Zimmer described as a "very, very productive offseason" Thursday, capping the third and final day of a mandatory minicamp with a barbecue with alumni, including 2015 Hall of Fame inductee Mick Tingelhoff.

The catered lunch by Lynch BBQ Company of Waucoma, Iowa, offered a chance to revisit the past with current players and coaches excited regarding the future. The Vikings are scheduled to begin training camp July 25, launching the team's 50th camp at Minnesota State University, Mankato.

Their first time on the field against an opponent will be against Pittsburgh in the Hall of Fame Game on Aug. 9, a day after Tingelhoff is enshrined in Canton, Ohio.

"I think our guys worked real hard, I think we paid attention," Zimmer said. "We did a good job in the weight room. We did a good job off of the field. I think it was a good way to finish, we have a lot of alumni out here today, including our newest Viking Hall of Famer, Mick Tingelhoff. It was kind of nice for the guys to see.

"I asked them to get ready for a long, physical training camp," Zimmer added. "We are trying to build a smart, tough, aggressive football team that knows how to play in crucial situations, and that was part of our offseason emphasis."

The Vikings began their voluntary offseason program in April and progressed to the three-day mandatory minicamp this week. Zimmer wanted to build on the installation of offensive and defensive systems from a year ago, and said players were able to practice faster. Much of Thursday's work was in the red zone. The offense looked crisp on timing routes, and the defense challenged.

Throughout the program, the Vikings pushed tempo, worked on offensive wrinkles and showed the ability to think and move on defense. The general belief is that the team improved during the program and remained fairly healthy for when training camp opens.

Adrian Peterson returned to Winter Park earlier this month and impressed teammates, coaches and observers with his cuts, speed and involvement in the passing game. Peterson said running backs coach Kirby Wilson helped him pick up on a couple of "curve balls" that have been added and said he saw Zimmer smile more often during this offseason program.

"I've seen a little difference. He's a little more open," Peterson said. "He's always seemed to have a sense of humor to me in the short time I was around him last year, but even more so I see him walking around, talking with guys and see a smile on his face from time to time.

"Normally he has that serious face on, but that's good," Peterson added. "Guys feel comfortable around him, but with that, you see that guys respect him so it's nothing that's being done that's disrespectful. They know what level to go to."

Peterson said he feels like he fields a question about increased involvement as a target in the pass game each offseason, and this year was no exception.

"I was looking forward to it last year with this offense," Peterson said. "The running back is going to be in position to definitely rack up his receptions. I'm looking forward to doing that. We'll see a lot more of it in training camp and when the season starts."  

D-Line rotations developing

Earlier Thursday, Zimmer was a guest of Voice of the Vikings Paul Allen on the 9 to Noon show on KFAN. Allen asked Zimmer if all the extra reps for second-year pro Scott Crichton and rookie Danielle Hunter in filling in while Brian Robison and Everson Griffen were limited this spring would help the depth and rotation on the line.

"It's not just with the defensive ends," Zimmer told Allen. "(Defensive tackle) Linval Joseph looks so much better. Last year he came in and learned a new system and then he had the injury that kept him sidelined and forced him to miss all of this stuff. He missed a lot of it because he had a shoulder injury coming in, but he looks very good, and Sharrif (Floyd) looks very good."

Joseph and Floyd were the starters last season, but the Vikings benefitted from a rotation with Tom Johnson and Shamar Stephen in 2014. This season, the Vikings wouldn't mind if Griffen and Robison don't log more than 900 snaps with improved depth. Griffen fully participated, and Robison partially participated this week.

Praise for the defensive or offensive line at this time of year is governed by the fact that players don't wear pads and go full contact during the offseason program. Zimmer said padded practices in camp will be a better indicator.

Utility player

The phrase "utility player" is most often associated with baseball, but defensive back Shaun Prater worked at outside corner, the slot corner and both safety positions this spring.

"I just love playing football. I really don't care where I play," Prater said. "Some people say they like playing left side corner over right side corner. I don't care. You can toss me anywhere on the field.

"I just show up and they tell me where to go," Prater added. "I said, 'Alright, I'll learn it, I'll play it and give you everything I have.' "

Prater joined the Vikings in 2013 but was originally drafted out of Iowa by a Cincinnati team in 2012 with Zimmer as its defensive coordinator. He gained familiarity that season, despite going on injured reserve as a rookie.

The 2012 late spring also marked the first time the Omaha, Neb., native ever attended the College World Series, but he's put together a streak of hitting the annual event.

"I've been going there the last three years," Prater said. "I was just there last week so hopefully I can make it back for the championship."