One week in the books, with a full season to go. What have we learned about the Eagles as they make their first turn of 2015, with the preseason open against Indianapolis in sight?

There are many topics to touch on here, and we know how the scenarios can change so quickly. The Eagles have four games in front of them and they have some decisions to make in areas that are chock full of competiition. There is plenty to talk about ...

• Rookie cornerback JaCorey Shepherd went down late in Sunday's training session at Lincoln Financial Field and he is likely to have an MRI on Monday to clarify the situation. It didn't look pretty. A sideline play with Shepherd and running back Darren Sproles ended with Shepherd on the ground and, after a few minutes, being taken off the field on a cart. We'll keep our fingers crossed. The Eagles are high on Shepherd, who had seemingly moved into the first-team role as the defense's nickel cornerback. If Shepherd is seriously injured, the Eagles have some options. Jaylen Watkins, the second-year man from Florida, is one. Veteran E.J. Biggers is another. Maybe rookie Eric Rowe develops and Nolan Carroll moves inside. The Eagles take so many defensive reps and move so many players around that they should be equipped to cover for any losses in the secondary. But, no doubt, should Shepherd be out it would be a loss. The Eagles are high on the sixth-round draft pick who has emerged as an early summer bright spot from what could be a very productive draft class this season.
• Speaking of Carroll, there isn't a more improved player on this defense. He has responded so well to secondary coach Cory Undlin's mandate to be more physical and to play press coverage at the line of scrimmage. Carroll was moved around a bunch last year and at times was more of a quasi-linebacker than a cornerback, and he sacrificed a lot for the defense. Now he's someone the Eagles are really counting on to be a stopper in the secondary, no matter the role.

• Tight end Zach Ertz has been outstanding in Training Camp, as everyone expected. He and quarterback Sam Bradford have a good thing going and it is obvious that Bradford has a lot of trust in Ertz, who has seemed to make a big play or three every day in camp. The Eagles are going to get some good matchups with Ertz this season, and if they couple Darren Sproles with Ertz in space, boy, it's going to be tough for defenses to cover both of those players in the middle of the field with linebackers and safeties.

• Walter Thurmond had, unofficially, three interceptions and a pass defensed in Sunday's trainng session. He seems to be settling in pretty well at safety, and the next test, a very good one, comes Sunday against Indianapolis.

• Matt Barkley or Tim Tebow for the No. 3 quarterback job? Both have had their moments in Training Camp, but let's be real: The job will be decided in the preseason games. Starting Sunday at 1 p.m. (on NBC 10 in Philadelphia), the preseason games are must-see TV. That is, if you aren't at Lincoln Financial Field. And judging by the 43,000 fans who were on hand on Sunday, the fans are going to be at the game.

• There is no clear-cut leader for the job at right offensive guard. The Eagles are rolling in a bunch of candidates, and on Sunday veteran Julian Vandervelde took the reps with the first-team offense. Who will claim the job? Could be Matt Tobin, or Andrew Gardner or John Moffitt or even Vandervelde. We'll see. It would help the continuity of the group to have it settled by the third preseason game, but who knows? Someone has to step ahead of the competition for that to happen. In the meantime, the Eagles are moving the players in and giving reps to as many players as they possibly can.

• Josh Huff has grown leaps and bounds in his second season at wide receiver. Leaps and bounds. He has become more consistent and when you combine that with his natural explosiveness and strength, it's a good package. Huff and Riley Cooper are taking the reps outside as the starting wide receivers and the ever-impressive Jordan Matthews has been in the slot. Nelson Agholor is coming on. Miles Austin has had some good moments. Rasheed Bailey opened some eyes on Sunday. While there isn't a "star" here, the wide receivers appear to be deeper and more versatile than in Chip Kelly's first two seasons.

• What's the word on linebacker Marcus Smith? He's got to show up in the preseason games, no doubt. The coaches are saying he's more physical and that he has the scheme down. Now it's about going into a game and getting to the football.

• This is the best group of running backs the Eagles have had in a long, long time. It's not just about DeMarco Murray and Ryan Mathews. Sproles is going to move around the formation in a big way. If the Eagles keep a fourth back, Kenjon Barner and Raheem Mostert have played well since the spring. My guess is that the Eagles go with three backs on the 53-man roster and keep two running backs on the practice squad. It's just a guess, of course.

• Finally, a word on Bradford. He looks better and better every day. He can sling it and his timing is there and the accuracy is strong. How much will Kelly play Bradford in the preseason games? Maybe not a whole lot. Bradford gets a ton of reps each day in training. He looks so good. Believe all of the reports you read. At the same time, understand that it's all about keeping Bradford healthy and that the entire complexion of his analysis changes when the defense can hit him and tackle him.