Philadelphia Eagles Coach Chip Kelly expects to play at a fast tempo again entering his second season. (AP Photo/Matt Rourke)

PHILADELPHIA—Practices are loud at the Philadelphia Eagles’ training camp. And they’re fast.

Music blared from gigantic speakers here early Friday afternoon, an assault on the eardrums even with those speakers sitting on the ground two fields from where the Eagles were doing their work. No time was wasted as they ran through full team drills under the watchful eye of second-year Coach Chip Kelly. The ball was spotted on the turf immediately after a play was over, and players rushed to the line of scrimmage for the next snap justlikethat. The music was interrupted periodically by a voice making an announcement over the speakers of “Last play!” for a particular set, as if to warn the next group of players that they’d better be ready so as not to slow the lickety-split pace.

That’s pretty much how it was for the Eagles last season in Kelly’s rookie year as an NFL coach. They moved quickly, as Kelly brought his fast-break offensive system from the college ranks at Oregon. And the success that Kelly and his system had, as the Eagles ranked second in the league in total offense and won the NFC East, amounted to a loud, bold declaration that he would be a force to be reckoned with in professional football rather than the next coming of Lou Holtz, Steve Spurrier or Nick Saban, coaches who failed to duplicate their college exploits at the next level.

So as Kelly enters Year 2 in Philadelphia, the question becomes: Can he stay a step ahead of NFL defensive coordinators? The job could be tougher now. Those defensive coaches have had time to digest and analyze what Kelly is doing and to try to devise ways to slow down his offense.

The Eagles say they’re counting on Kelly.

“It won’t surprise many people this year as far as the pace and what they do,” Philadelphia safety Malcolm Jenkins said of his team’s offense as he stood on the field after Friday’s practice. “But it’s still unusual. Until the rest of the league does it, it’s still something that you have to prepare differently for when you play the Eagles. And I think that gives us somewhat of an advantage because you don’t see it every week. But you know, Chip will find ways to adapt when people do catch on to that. He’ll adapt and do something else. The pace is one thing. But there’s a lot of other caveats in our offense that really give you problems and give you fits as a defense.”

The adjustments and readjustments by Kelly and opposing defensive coaches should be fascinating to watch, according to former Eagles linebacker Ike Reese.

“That’s one of the big questions… is how much did the offseason help out these defensive coordinators around the league getting a chance to see what Chip can bring to the table,” said Reese, now a radio talk-show host on Philadelphia station WIP. “But at the same time, we forget that Chip’s an innovator. And I’m sure he didn’t have in his full playbook last year. He just couldn’t get it done in his first year. So Chip has also had a chance to see the defensive coordinators around the league and what they like doing as a defense, and counter that with more offensive diversity. It’ll be a great chess match to see just how much the gap has been closed from last year to this year, or if Chip has been able to extend that gap a little bit.”

The Eagles and other teams with hurry-up offensive approaches test not only a defense’s stamina and conditioning, but also its ability to make quick decisions, come up with X’s-and-O’s adjustments on the fly and get the right combinations of players on the field in an era of specialization. What will the defensive remedies be? There were some accusations last season of opposing defensive players faking injuries to slow the Eagles’ pace. But short of that, the best solution seems to be keeping the Eagles from getting first downs and getting Kelly’s offense off the field.

There was some speculation entering last season that NFL game officials wouldn’t allow the Eagles and other up-tempo offenses to snap the ball as quickly as they’d like. But Kelly said Friday he had no such problems last season and doesn’t anticipate any this year.

“I didn’t have any issues with the officials last year,” Kelly said. “And that wasn’t anything that was brought up in our league meeting. We never really talked about that…. That wasn’t a discussion with any of the coaches that I was aware of.”

Kelly said his offense will evolve but mostly because of changes to the Eagles’ roster. They released speedy wide receiver DeSean Jackson, in a highly scrutinized move, even after a season in which Jackson topped 1,300 receiving yards. Wideout Jeremy Maclin returns after a 2013 season lost to a knee injury. Versatile running back Darren Sproles arrived via a trade with the New Orleans Saints.

“It always changes,” Kelly said. “I’ve said it from day one: Your offense is always personnel-driven. The biggest thing you have to do is identify the skill sets that you have and then adjust to those skill sets. And that’s what football’s always been. Our offense has changed every year I’ve been in charge of the offense whether I was at New Hampshire, at Oregon or here. Our quarterbacks had different skill sets. We ran more power running plays when Jeremiah Masoli was our quarterback [at Oregon]. He was an outstanding runner. He was different than Darron Thomas. Darron was more of a pocket passer and could do some different things. Darron was actually really good at throwing on the run, also.

“So whatever their strengths are, you try to cater to those. That’ll always be the case. We’ve got some new guys. So we’ll tweak what we’re doing based on what their skill sets are as we continue to evaluate here and say, ‘Hey, how do we run this?… We didn’t do this much in the past. But now that we’ve got a different type of person in that situation, let’s do this.’ ”

Kelly said he won’t make changes, however, merely in a bid to stay ahead of the defenses that are sure to adjust to him.

“We don’t change for change sake,” he said. “I mean, you self-scout yourself and you’re five for five on a certain pass pattern, you don’t say, ‘We’re not gonna call it again because they know it’s coming.’ You know, they still have to stop you in certain situations. It’s still football. That’s just the talking season. Guys will say they’ve had time to figure it out. I’ve said it since day one: We don’t do anything revolutionary offensively. We run inside zone or outside zone. We run a sweep play. We run a power play. We’ve got a five-step [passing] game. We’ve got a three-step game. We run some screens. We’re not doing anything that has never been done before in football.”

Jenkins, who played against the Eagles in last season’s playoffs as a member of the New Orleans Saints and now practices daily against Kelly’s offense, said Kelly’s system is sufficiently malleable to do whatever is needed.

“There is no set offense,” Jenkins said. “It’s really very fluid and very adaptable. So whatever defenses pose and present, Chip will find a way to take something else.”

Much depends on the continued productivity of tailback LeSean McCoy, the NFL’s leading rusher last season, and quarterback Nick Foles, the league’s highest-rated passer who threw 27 touchdown passes and only two interceptions as a second-year pro.

Reese said the overall talent level on this season’s offense is improved from last year, in his view.

“I sort of think it’s a better group overall when you look at the talent,” Reese said. “Now, had Maclin stayed healthy last year and you add him into the equation with that group, then you’re talking about something different. But because Maclin wasn’t there, there wasn’t a lot of depth behind those guys skill-wise last year. And this year, I think they do have depth.

“They have two good young receivers. The tight ends are gonna be much better year. I expect [second-year tight end] Zach Ertz to have a breakout season this year. [Wide receiver Riley] Cooper, we’ll have to see if he can repeat what he did last year. And Maclin is a guy that’s been on the cusp of being a 1,000-yard receiver several times before last year. In this offense, I expect him to sort of break that this year. And then Darren Sproles, are you kidding me? Darren Sproles is a matchup nightmare for any safety or linebacker in the NFL, even at 31 years old.”