The Vikings ended three days of early work for rookies and quarterbacks Thursday, before they welcome fans for the first open practice of training camp when the full team assembles Friday afternoon.

As the Vikings start their slate of 16 open practices, they've seen fans scoop up nearly 72,000 of their 80,000 available tickets for the sessions.

Only reserved seats remain for the Vikings' first three open practices Friday, Saturday and Sunday, as well as for their night practice in TCO Stadium on Aug. 3.

Free general admission seats remain available for most practices; fans can claim those seats or pay for a reserved seat starting at $15 on the Vikings' website.

Last year, Vikings officials adjusted their ticket availability during training camp, releasing more seats as no-shows reduced the actual number of fans in the stands.

The team could make additional tickets available again in 2019, based on the no-show numbers it experiences during the first upcoming days of camp.

Fans can reserve tickets as late as the day of the practice they wish to attend, provided tickets are still available.

The Vikings will close their morning walk-throughs to the public in 2019, opening only their afternoon practice sessions to fans in an effort to cut down on wait time for fans between walk-throughs and practices.

Summer sessions

Now a father of two boys as he heads into his eighth NFL season, quarterback Kirk Cousins knows as well as anyone how zealously players must guard their downtime between the end of minicamp in June and the start of training camp in late July.

It's why Cousins didn't make a concerted effort to pull all of his receivers together over the past few weeks for a throwing session near his home in Holland, Mich.

"I wasn't going to ask anybody to get on a plane and come fly there, just because the summer weeks are so precious and guys want to be with their families," he said. "If I did say, 'Hey, come here,' they would be there, but I want them to be able to enjoy that time with their families."

Still, Cousins was able to get in some extra offseason work with a few of his targets who live within driving distance of western Michigan — wide receivers Chad Beebe and Laquon Treadwell in Chicago, and tight end Tyler Conklin in the eastern part of Michigan.

"They're all kind of within a two- to three-hour drive of where I am, so I said, 'Why don't you guys come up? We'll throw a little bit, connect,' " Cousins said. "We have a lot of time here to get together, so just because they were a short drive, I thought it was worth it, maybe."

Advanced RB duties

As the Vikings get to work with a youthful group of running backs Friday — and especially after they begin padded practices Sunday — their ball carriers will undergo a real-time indoctrination into the nuances of pass protection, against one of the NFL's top defenses.

"The biggest thing for those two guys, Alexander [Mattison] and Mike [Boone], is really the protection part of things, the pass routes that they have to run, making sure they're precise on those," coach Mike Zimmer said.

"Carrying the ball for those guys is pretty natural. The other parts really have to get in certain routes, the read routes [where] they have to go out instead of in, they have to block this linebacker or that linebacker or whichever one comes, or the pass-off with the offensive line. Those things are all things that take the most time for running backs."