INDIANAPOLIS – The NFL will permit teams to use one of their precious draft picks on Oklahoma running back Joe Mixon, who in turn will be allowed to earn a seven-figure salary while employed in the league.

But the NFL did not let the polarizing prospect attend its annual job fair, creating perhaps the biggest talker at this week's scouting combine.

While some NFL coaches and general managers the past two days have publicly echoed the company line, others have been outspoken about the league's decision to not invite Mixon, Mississippi quarterback Chad Kelly and other draft prospects with varying degrees of off-the-field issues.

Detroit Lions General Manager Bob Quinn called the decision to leave Mixon and others home, which is a change in the NFL's philosophy this year, "really disappointing" and said it's "really unfair" to those prospects.

"We come here to see the best college football players," Quinn said. "So there's 330-340-some-odd players here and for [Mixon] not being here because of those issues, personally I don't think that's real fair because we have a lot of investigation that we want to do on him."

Mixon's "issues" are significant. In 2014, the Oklahoma Sooners standout knocked a young woman, a fellow student, to the floor with a punch at an establishment off campus after she shoved him in the chest. Mixon, then a freshman, was charged with a misdemeanor at the time of the incident and the University of Oklahoma suspended him for the entire 2014 season.

In December, as his final season with the Sooners was coming to a close, his story entered the national spotlight when surveillance video of the ugly incident was finally released. Last month, he publicly apologized to the victim, Amelia Molitor, who suffered four fractured bones in her face.

The NFL, three years removed from the Ray Rice scandal, then made the decision to not invite Mixon to the combine, forcing teams to interview him on their own time and their own dime before April's draft.

Baltimore coach John Harbaugh, who was with the Ravens when Rice punched his then-fiancée in a New Jersey casino and was cut by the team when video of that incident become public, said they "respect the NFL's priorities and what they're trying to accomplish" with the new policy.

"Our job as a coach, or a scouting staff, is to turn over every stone, to find out everything we can about every single guy, regardless of whether they're here at the combine or not, for whatever reason," Harbaugh said.

Combine interviews are key, but they are only one piece of the puzzle as teams determine whether to add any individual to their organization.

"Whenever you make a personnel decision, probably in any part of life, you're making a prediction. It's a choice going forward," Harbaugh said. "What's this person going to become? What are they going to fulfill? What are their dreams and aspirations? What do they hold to be valuable? What are their values? The past is a little bit of a determiner of that."

Like the Ravens, the Vikings are also put in a delicate situation when it comes to considering players with past legal issues and character concerns after weathering running back Adrian Peterson's child-abuse case in 2014.

General Manager Rick Spielman, not wanting to ruffle feathers, declined to comment on the new policy. But coach Mike Zimmer expressed the same sentiment as Harbaugh, saying the Vikings will look into Mixon and other non-combine players with troubling backgrounds away from Indianapolis.

"I know it would be easier for the [teams] if all the guys" were here, Zimmer said. But "there's a lot of non-combine guys that you have to go out and evaluate and talk to and you get tested. It's all part of the process."

The Vikings have likely been doing their homework on Mixon for a while, starting with the area scouts who drop in at schools during the fall. That vetting process picks up once an underclassman such as Mixon officially goes pro. Spielman and the top scouting execs might do deep digging, too, especially because running back is now a major area of need for them.

The Vikings also employ psychologists to help evaluate their makeup.

Zimmer, who is hands-on in the scouting process in the weeks leading up to the draft, sometimes sits down with players, too, though it is unclear if he has or will at any point have a conversation with Mixon, a 6-1, 225-pounder who rushed for 1,274 yards and 10 touchdowns in 2016.

"You sit down and talk to them man to man. You tell them your expectations and make sure they understand your expectations," he said generally. "And then most of the time I'm a guy that if I feel like they're being honest with me and straightforward with me, then I'm going to have their back as well."

Zimmer said Spielman will discuss prospects with off-the-field issues with team ownership if they want to keep them on their draft board.

"None of us are perfect," he said. "But yeah, some things are detrimental."

To be able to sell a prospect with a past such as Mixon's to owners (and in some cases their wives and family) and then to a fan base, NFL teams need more time with that player than the quick meet-and-greets in Indianapolis.

But many feel that these 15-minute chunks of face time are arguably the most important part of the combine from a scouting perspective, which is why some team executives have voiced their frustration this week.

"We're going to have to use resources now, but that's how they want to do it and I'm not going to argue with it," Tampa Bay Buccaneers GM Jason Licht said. "That's the process. But … we'll vet every single player."