ALLEN PARK -- The Detroit Lions wrap up the first round of Organized Team Activities on Thursday at team headquarters. The late-morning practice will be open to reporters, which provides the first opportunity to see the squad on the field under new coach Matt Patricia.

Here are five things to watch:

How 'bout that defense: In another offseason of sweeping change, perhaps nothing will look more different than Detroit's defense. It's undergoing a major makeover under new coach Matt Patricia, and GM Bob Quinn has already hinted that we're in for some surprises. Detroit is expected to be ditching its 4-3 base for a more versatile look that features a lot of three-man fronts. Which means the big guys up front should look and operate much differently, with all kinds of linebackers filling in behind them. Devon Kennard was the big free-agent signing this year, and he's expected to line up all over the front, but especially as an EDGE pass rusher. And there's a whole fleet of new linebackers who have joined him, including Jonathan Freeny and Trevor Bates, a couple more ex-Pats, as well as Christian Jones. Don't forget about undrafted rookies like Chad Meredith either, nor the return of fellas like Jalen Reeves-Mayin. There are so many moving parts all over the place in this defense, both in terms of scheme and personnel, it's going to be fascinating to see how they fit together.

Where's Frank? Frank Ragnow was drafted in the first round, which means he's going to be expected to start right away. That's what happened with Taylor Decker at left tackle in 2016, and Jarrad Davis at middle linebacker in 2017. Both players were starting at their respective positions on the first day of OTAs open to reporters, and neither left the starting lineup throughout their rookie seasons. But with Ragnow, there's still an air of mystery about the plan for him. He mostly played center in college -- in fact, he was the best center in the country according to ProFootballFocus -- but he also played some guard. And with Graham Glasgow able to play both positions too, Detroit has options when it comes to configuring its offensive line.

New-look backfield: Bob Quinn was in New England 16 years, and in all that time, the Patriots took a running back in the first two rounds twice. That's it. Now not only has he taken Kerryon Johnson in the second round, but actually gave up a fourth-round pick to go get him too -- in a draft where he was already sitting on the fewest picks in the league. Quite obviously, Quinn loves Johnson, and believes he's going to have a major role immediately. It wouldn't be a surprise if he moved into the starting lineup at some point, though that point is unlikely to be today with veteran power back LeGarrette Blount aboard, plus Ameer Abdullah and Theo Riddick back. It will be interesting to see the rookie on the field though, and what the Lions are doing blocking-wise in front of him.

Possible position changes: Versatility might be the most valuable commodity in the Patricia era, which means there's still a lot of uncertainty about who will play where. That's especially true in the defensive backfield. Quandre Diggs could stay in the nickel, where he played most of the last 3.5 years, although he was fabulous at safety down the stretch last year too. DeShawn Shead could play in the slot too, or on the outside. Nevin Lawson too. And I'm especially intrigued to see what's up with Miles Killebrew, who looked promising at safety as a rookie in 2016, but faded last year. Could he be a candidate for a change to, say, linebacker? Because with Glover Quin and Tavon Wilson back, Diggs still an option and now third-round pick Tracy Walker aboard, he's going to have a difficult time seeing the field on the back line.

Who's going to play tight end? The Lions return a whole lot of experience at almost every position. Tight end is not one of those positions. They cut one starter, Eric Ebron, to save money before the start of free agency. Then were outbid by Cleveland for the other starter, Darren Fells. Their returners, led by Michael Roberts, combine for three career catches. Their new acquisitions, led by Luke Willson and Levine Toiolo, have never caught more than 33 passes in a year. This competition is completely wide open, and it'll be fascinating to see how Detroit goes about settling it.