By Kevin Durso, Sports Talk Philly editor 
If someone told you that at the quarter-point of the season, the Eagles would be 3-1, you'd take it every time, right?
Truth be told, sitting at 3-1 before even having to take the field against an NFC East opponent is an excellent start to the season.
But what happens when you realize that that one loss was a game within your grasp, where self-inflicted wounds came into play? It becomes a little harder to take.
The Eagles missed an opportunity to go to 4-0 on Sunday and while it may not affect the outlook of their season at this moment, it has to serve as a lesson for an Eagles team trying to grow together.
There were several different points where the Eagles let this opportunity slip away.
The entire first half could be blamed solely on the defense and perhaps a decision to leave one player on the field too much and another off the field entirely.
The game changed when Nigel Bradham got on the field. Suddenly, the Lions couldn't run. The screen game to Theo Riddick, which worked very well in the first half, became ineffective. The passing game was held in check. The Lions got a total of three points in the second half. Three. It's impressive.
But the first half was another story. It was Thanksgiving 2015 all over again. Three drives, three touchdowns. Mychal Kendricks was a big part of that. While the veteran linebacker has never been the best in coverage, he's taken a step backwards in every aspect of the game. And even though it wasn't working with him on the field, the Eagles kept Bradham and Jordan Hicks on the sidelines.
The second point of focus comes from the offense in the second half. The defense, to this point, still didn't have a stop. Their first possession, with the Eagles now back within four, resulted in a fumble recovery. The ball was on the Lions 16 yard line. The Eagles gained two yards on the next three plays and settled for three points to cut the lead to one.
The play on that drive that stands out is the third-down play, an incomplete pass from Carson Wentz to Dorial Green–Beckham. 'DGB' has plenty of potential, and earlier in the game had shown it with a stiff arm move that produced extra yardage on a big play for the Eagles. On this play, for the second straight week, Green-Beckham dropped a potential touchdown pass. Those are plays the Eagles wide receivers need to make and quite possibly one of the only similarities this year's team has to last year's.
The last point of focus comes before the costly plays that turned the game in the Lions favor. Because as the Eagles were driving to take the lead, Ryan Mathews had his best play of the game, a 23-yard run to the Lions 13 yard line. A field goal from there was automatic. A touchdown would provide enough separation to force a touchdown drive to beat you. Given the way the Eagles defense was playing in the second half, the likelihood the Lions would put it all together then was not good.
But on the play, the penalty flag hurt the Eagles again. Brandon Brooks was called for offensive holding, some 20 yards from the line of scrimmage. It negated the 23-yard run and put the Eagles back on the Lions 36, still in field-goal range, but needing so much more for the touchdown. They had to settle for the field goal two plays later, enough to give them the lead, but only by two points.
Penalties overall were a big problem for the Eagles, and while the officiating crew was certainly erroneous on several occasions – calling Connor Barwin for an ineligible man downfield penalty? Really? — being called for 14 penalties will almost always do a team in on the scoreboard. That's something that has to be cleaned up going forward.
What we learned from Sunday's loss is that this is still a team that is learning. But this is also a team that is growing.
Doug Pederson is right when he says this is not last year's team, because there is an actual bond that this team has that was non-existent a year ago. The players couldn't relate to Chip Kelly. There were players that weren't fits for the system. There were too many pieces out of place.
But what this team has is a clear leader at quarterback. The final play aside, Carson Wentz was a leader on Sunday. He looked adversity in the eye and led his team back with three tremendously orchestrated drives, one after the Lions went ahead by two scores just two drives into the game, one right before the half that resulted in a field goal and the first drive of the second half. If he had that last play over again, he would probably find a checkdown option, take shorter yardage and get back to the line to try to get the Eagles into field goal range. The rookie is going to have to learn some things.
Just like Wentz, the Eagles have a foundation on the sidelines in Doug Pederson. One thing Chip Kelly's teams did not do well was make adjustments. The second half was all about adjustments and the Eagles were able to take the lead because of successful changes to the game plan and rotations on the field.
All of that being said, all of the things that are different about this year's team, it's a loss that should have been a win. And it's a decision that hurts because of how it slipped away. But there's something that says the Eagles will learn from this missed opportunity, and that's the solace from defeat on Sunday.
