The Chip Kelly era has gotten off to a shaky start so far. There have been a few positive moments, such as a fairly solid draft and the creation of an offense that seems to perfectly fit Michael Vick's skill set.
However, Kelly has made some very significant errors so far. These mistakes can be overcome, but Kelly has failed to capitalize on opportunities to rebuild this team more quickly through personnel and coaching decisions.
Here are five of Kelly's biggest blunders of the Philadelphia Eagles' 2013 offseason.
Emmanuel Acho lit it up in the preseason. Most notably, against the New York Jets, he had 11 tackles, a sack and a forced fumble. Conventional wisdom would say that he had certainly earned a roster spot and, perhaps, even some regular-season playing time.
Instead, Kelly chose to release Acho and retain Casey Matthews, the fourth-round pick who fell drastically short of expectations in Philly ever since his first game.
This move is simply baffling. Matthews has not had a poor preseason, but Acho's was superior. Acho totaled more tackles than Matthews against the Carolina Panthers (three to Matthews' zero), the Jacksonville Jaguars (six to Matthews' four), and the Jets (11 to Matthews' two).
Matthews has had his chances to show himself as an NFL-caliber linebacker, and he has consistently failed to play well. His primary asset is on special teams and in nickel situations. Acho clearly had more upside and outplayed him. He should not have been cut.
Anyone who had paid attention during training camp and the preseason could see how phenomenally talented both receivers were. Shepard was as elusive as they come after the catch and capable of making highlight-reel circus catches based on my observations at training camp.
Salas, too, showed impressive and reliable hands and an uncanny ability to get separation.
Yet, Kelly chose to leave both off the active roster, instead retaining Jeff Maehl.
Maehl played well in the final game of the preseason, hauling in eight receptions for 61 yards. But Shepard and Salas have both had incredibly productive training camps and reliable training camps from my observation. Failing to place a single one on the active roster is a mistake.
At least Salas was retained on the practice squad. Shepard was allowed to walk and was shortly picked up by the Tampa Bay Buccaneers, who are now very lucky to have an under-the-radar playmaker on their roster.
Losing Jeremy Maclin was a huge blow to this receiving corps, and the Eagles missed out on a great opportunity to augment their wide receiver depth. They will now be in trouble if DeSean Jackson were to miss any significant time.
When the Eagles brought two new tight ends aboard, Zach Ertz through the draft and James Casey through free agency, it was assumed that Clay Harbor's days in Philly were over.
Surely, the Eagles would never keep more than three tight ends, and Harbor, an excellent blocker and underrated route-runner, would be an unfortunate casualty of the new regime.
Well, months later, the Eagles surprised all by keeping four tight ends. But they surprised everyone more by still choosing to release Clay Harbor.
Instead, they decided to retain Emil Igwenagu, an incredibly inexperienced tight end who has not had a single reception going into his second NFL season. In the preseason, he failed to catch more than one pass in any of the games, which is hardly enough to justify keeping him over the more experienced Harbor.
You can practice fundamentals all you want, but it's entirely different in a real game. When players are on the field, having to think quickly and rely on instinct, muscle memory will be invaluable in bringing down elusive ball-carriers.
In stark contrast to Andy Reid training camps, where tackling was a huge part of practice, Kelly has chosen to neglect consistently tackling in camp until the preseason, according to Geoff Mosher of CSNPhilly.com, relying mostly on drills.
This could be Kelly's most costly mistake of the offseason.
Unlike college football, where you can often rely upon the talent of the defenders to dominate less talented opponents, everyone in the NFL is an incredible athlete. Therefore, tackling must be made a priority in camp to prevent big plays from the offense.
Inconsistency on defense has already shown up in the preseason, most notably in a 51-yard touchdown run by LeGarrette Blount, helped largely by several missed tackles from Eagles defenders.
The talent on the defensive side of the ball is lacking, and to make matters worse, tackling was not made a top priority. Expect to see a ton of arm tackles and one of the bottom-ranked defenses from the Eagles in 2013.
This is not in any way an attack on Nick Foles. Foles is an excellent player and has had an impressive preseason (except for his last game). Foles will be an excellent backup to Michael Vick.
However, Foles' best value is not as a second-string quarterback. His best value is in the form of trade bait.
Foles is just coming off a quarterback battle that he lost because his opponent, Vick, significantly stepped up his game, rather than as the result of poor play from Foles. Following impressive preseason performances, his value will never be higher than it was when Vick was named the starter.
Plenty of NFL franchises are desperate for a starting-caliber quarterback. When teams like the Oakland Raiders are resorting to an undeveloped Terrelle Pryor, Kelly made a critical error when not capitalizing on an opportunity to get great value for the backup quarterback.
While Foles can always be traded next offseason, by then, his value may be significantly lower. It's expected to be an excellent quarterback class, containing the likes of Terry Bridgewater, Tajh Boyd, Johnny Manziel, and AJ McCarron just to name a few.
Next season, many NFL franchises will turn to the draft to solve their quarterback woes. The Eagles would be lucky to get as high as a fifth-round pick for Foles and would likely have to settle for an even lower draft pick.
Follow Yueh Ho on Twitter @YuehHo.