That moved Aaron Colvin to the other safety position and Harris as the odd man out.
But weak side linebacker Travis Lewis' injury has been the next rocky twist, one that has put the responsibility back on the 5-foot-11, 207-pound defensive back from Lawton, Okla.
"First thing that went through my head is now I know I'm going to be back there at free safety," Harris said. "You know, I knew that they were going to move--I kind of had that feeling that they were going to move Tony back to Sam, nickel a lot more, so I just knew I had to step my game up at the free safety position, also learn the strong safety position as well, just knowing both positions and knowing I was going to have to step up in that role."
And stepping up and filling a role is something he's done before.
He responded with a career-high eight tackles in OU's 47-41 triumph over the Oklahoma State Cowboys.
That's something that's given him confidence throughout this fall camp so far considering the whirlwind of events he's experienced.
"I take it as me just taking it as a learning role last year and coming in now and being at those starting positions, competing for those starting positions," Harris said. "You know, I have to take that role knowing that I have had that playing experience. I have to use it as my experience on the field this year."
It's also offered him a certain level of comfortability.
"Yes, I would say I am a lot more comfortable," Harris said. "Just with those reps, you don't go into the game as nervous. You don't go into the practices not knowing that you know those guys trust you back there, and the other guys on the defense and they're not looking back like, "Well, we might have to cover for this safety.'
"You know, they can look back and say, ‘Well, this guy here, he can take care of his business back there.' And that's one thing I have to do. Just taking those reps last year and then coming into this season."
Something else that has aided in his progress as a safety this fall is the guys he worked behind in previous years.
Players so often talk about leadership and accountability, and he's developed those traits not only by melding within defensive coordinator Brent Venables' system, but also from former Sooners, Nelson and current Denver Broncos defensive back Quinton Carter.
"I mean, you just learn leadership," Harris said. "You learn a lot of just game time experience, game time reactions. You know, I actually roomed with Q. Carter last year at away games and just learning how the game goes, how the pace goes and just watching these guys and learning that leadership role and do what it has to take on the field, so just being able to take those things in from those guys is what we've learned.
"I think that's one thing that we did [also learn is reliability]. We relied on those guys just knowing that they could make up for lost plays or make up for plays that might have got busted. You know, and that's one thing that we have to do as safeties is come in and do that and be in that last line of defense of defensive backs. You know, we have to be reliable, and I think that's one thing we have to look at as far as all the safeties and all the DB's as far as corners and with those guys being gone, we all have to take that role."
Another the role he's been seeking out is that of a vocal leader, especially in Lewis' absence.
"Being able to just be a guy on the field that knows those type of things and knows what's going to happen, use my experience from the previous years and use my experience from playing with Travis and those other guys, just my coach being able to tell me that he needs that vocal leader out there [is important]," Harris said. "And I think that I can take that role."
One thing's for sure: his role on this team has become that much more important since the Sooners lost their major defensive leader.