THERE WAS a moment during Eagles practice on Tuesday when Carson Wentz lined up in the shotgun and tentatively pointed toward the middle of the defense, the way quarterbacks often do when they are identifying the MIKE linebacker. Whether that is actually what Wentz was doing is besides the point: What's relevant is that the young quarterback turned around and looked at coach Doug Pederson, who was standing behind him with a play sheet in his hand. Pederson nodded to confirm that the rookie was correct in whatever he was pointing at, and the play commenced.

There would be nothing extraordinary about such an interaction between a new coach and a new player, except that the new coach was replacing Chip Kelly, and, in Kelly's practices, you rarely saw that kind of thing. The eccentric run 'n' gun aficionado structured his workouts so that the vast majority of corrective coaching took place in the film room after practice. Kelly prioritized tempo in everything he did, and he thought that limiting disruptions during reps would enable him to maximize the number of reps each player got during a session. It might be a bit of a leap to fault that one aspect of Kelly's style for the plethora of breakdowns that plagued the Eagles last season, particularly on the offensive line. But it also would not be a surprise if it was a contributing factor.

Whatever the reality, the back-and-forth between Wentz and Pederson on Tuesday was a good example of the kind of unknown variables that make it difficult to project what this season has in store for the Eagles. Kelly was a radically different coach in fundamental ways. It's fair to say that we might not know what, exactly, this Eagles roster has in terms of personnel. Owner Jeffrey Lurie and football ops chief Howie Roseman seem to have placed ample faith in the notion that those radical differences were the primary culprit for their 7-9 finish last season, and perhaps the dynamic duo turns out to be correct. Maybe Jason Peters really can return to All-Pro form in a more conventional scheme. Maybe this has been a good offensive line all along, in terms of personnel. Same goes for the receivers. Maybe these guys are all tactile learners who simply needed to be shown rather than told what to do.

Of course, the inverse could also be true, and this roster could be worse than anybody imagined.

There's a tendency to view Kelly vs. Pederson as an either/or proposition. At this point, there doesn't seem to be much dispute that Kelly's scheme and system wore on his players. His refusal to adapt either one to the realities of the NFL was unfortunate: He's a bright coach with an intuitive feel for moving the football down the field. He just never seemed willing to tinker with any of his foundational principles, even when it seemed obvious to all who watched that defenses were adapting. Yet there's no guarantee that Pederson will be any better. His process is more conventional, but he certainly does not bring much political capital with him, given his meager coaching résumé.

One of the most interesting read-between-the-lines moments at the NovaCare Complex on Tuesday involved the news that Darren Sproles had been and would continue to sit out the voluntary workouts. The reason for his absence isn't exactly clear: A nebulous NFL Network report said the absence had something to do with trade offers the Eagles received during the draft, but Pederson insisted that the team had not shopped Sproles and that he wanted Sproles on the team. He also said Sproles has not asked to be traded.

"I think where he is in his career, I've been there before, too, where sometimes you want that break," Pederson said. "I know with him and his family being apart during the season, this is a time for him to really spend quality time with the family, and he knows what it takes to get himself ready to go, and I fully expect him to be here in a couple weeks."

At the same time, Sproles' absence at least raises the question of how inspired some of the troops are feeling as the Eagles prepare for 2016. Every 32-year-old running back is living on borrowed time, and the Eagles sacrificed several assets who might have helped them win in 2016 and 2017 to land a quarterback whom they say they want to develop slowly. Instead of using first-round picks in 2016 and 2017 to surround veterans such as Sproles with talent to win now, they spent them on a chance to win down the road, when Sproles will be sitting by a pool somewhere. Would it really surprise anybody if Sam Bradford wasn't the only player who watched the Eagles' offseason and thought, "What in the world are we doing, and, whatever it is, what's the point of me sticking around?"

Granted, the ultimate point is always money, which is why the Eagles probably aren't too concerned about Sproles. But if his decision to sit out OTAs is an indication of a psychology that exists elsewhere on the team, Pederson will have even more work in front of him than he might've thought.

At this point, the only thing we know is that 2016 will be a fascinating study in contrasts. For better, for worse, or for par.

@ByDavidMurphy