ALLEN PARK -- The Detroit Lions wrapped up their first round of Organized Team Activities on Thursday at team headquarters. And since they didn't open either of their first two practices to reporters, they were forced by league rules to open this one.

Here are some observations from the roughly two-hour workout.

-- Coach Matt Patricia said before practice he hasn't settled on a position for Frank Ragnow, and maybe that's true. But I'm betting it's not. Ragnow practiced exclusively at left guard during practice, which lines up with what I've heard from team sources as well as photos/video posted by the team itself from previous OTAs and rookie minicamp. I can't find a center snap from him anywhere, including all two hours on Thursday. Here's betting he eventually gets some snaps there so he has some versatility in case you-know-what happens, but he sure looks like a guard right now. Graham Glasgow was settled in at center -- the position many people in Allen Park believe is his future -- while Taylor Decker (left tackle), T.J. Lang (right guard) and Rick Wagner (right tackle) were at their usual posts.

-- Sometimes LeGarrette Blount went first in a particular period, and other times it was Kerryon Johnson. But it was always one or the other. Based on today's practice, those guys are the top two running backs right now. Theo Riddick continued to look really good as a pass-catcher, too, including beating Quandre Diggs for one nifty touchdown reception over the middle.

-- Of course, that relegates Ameer Abdullah to competing for one of the one or two remaining jobs in the backfield, along with Zach Zenner, Dwayne Washington and rookie fullback Nick Bawden. He did add some punt return work to his portfolio Thursday, which I haven't seen him do before. Golden Tate, Brandon Powell, TJ Jones and Teo Redding also shagged punts. Jamal Agnew, an All-Pro at the position last year, did take a couple punts early but sat out a later drill.

-- The offensive backfield had another surprising addition on Thursday: Nick Bellore. He played linebacker last year and was a staple on special teams, but also played 13 snaps as a fullback. On Thursday, it sure looked like he's making that a full-time thing. He was actually wearing a white offensive practice uniform, and I didn't see him do a lick at linebacker. Seems Nick Bawden, the seventh-round pick, might have some competition for the fullback job.

-- The defense was as varied and versatile as expected. My head was spinning from all the schematic and personnel changes, alternating between three- and four-man fronts. It's barely worth noting who was starting there, because it changed so much and so frequently. But it sure looks like they're going to run a lot of three-man fronts with linebacker Devon Kennard playing on the line as an EDGE rusher.

-- Luke Willson took the first rep at tight end, and he's going to get a long look for that top pass-catching role with Eric Ebron out. But don't discount Michael Roberts either. He caught just four passes last year, but there are a whole lot of people thinking he could be headed for a breakout. Tight end is a notoriously difficult position for rookies, first of all. He led the nation's tight ends in touchdown catches at Toledo, second of all. And now there's opportunity, with Ebron and Darren Fells out. On Thursday, he sure looked like he was capable too, spearing a couple nifty touchdown passes.

-- The practice had some notable departures from the Jim Caldwell era. One was the addition of two large TV screens that allowed Detroit to immediately evaluate players. There were also a couple new drills, including one that worked on the open-field tackling, and another that worked on the blitz pick-up. It featured the offensive line working against a three-man defensive line, plus two upright linebackers sandwiching the nose. Cornelius Washington played the nose with the ones in those drills, with Kerry Hyder and Anthony Zettel at defensive end. Jarrad Davis and Devon Kennard were the linebackers.

-- Another difference was the music playlist. The Jim Caldwell era featured mostly electronic music and rap (with edited lyrics). On Thursday, it was a lot of Metallica with some Pantera and Bush sprinkled in.

-- Breaking news: Kenny Golladay is still really big, and still really tough to stop in the red zone. We knew he was going to play right away based on what he did in those final 20 yards last summer, and Thursday was no different. Perhaps his best play was a touchdown catch over Darius Slay, and Darius Slay did little wrong on the play. He was right there. But Golladay is 6-foot-4, and there wasn't much Slay could do.

-- Safety Glover Quin was the only player not in attendance, although defensive end Ezekiel Ansah did very little, and nothing at all during team periods. Ansah, who has battled near-constant injuries the last two years, declined to comment after practice. Additionally, interior offensive lineman Joe Dahl and safety Tavon Wilson wore red no-contact jerseys.

-- With Quin out and Wilson limited, Miles Killebrew got a long burn with the first unit at safety. It did not go well. He was beat repeatedly by tight ends, including for touchdowns by Michael Roberts and Luke Willson, and Levine Toiolo would have scored on him too had he not dropped the ball in the end zone. It's premature to panic in any kind of way -- it was one practice in the middle of May, and there's still so much to like about Killebrew's size and speed. He's definitely a physical fit for this defense. But with third-round pick Tracy Walker aboard and all the other top safeties back, Killebrew's spot isn't guaranteed either.

-- Jake Rudock took all the second-team quarterback reps over Matt Cassel, and looked comfortable commanding the offense. That includes threading a touchdown pass to Jace Billingsley for one of the best plays of the day. I barely saw daylight, then saw Billingsley squirt out the other end for the score. It was a great pitch and catch.