No one doubted that Chip Kelly would bring major changes to the 49ers, and early reviews by the players are good, CSNBayArea's Matt Maiocco reports. He quotes Garrett Celek:

"In the past we had a lot of delay-of-games because either we’re not getting the play in time from upstairs or it’s just taking the quarterback too long to read the whole play out. Where now, it’s a lot quicker. We have hand signals, so you can’t have 15 words through hand signals, stuff like that. It’s got to be boom, boom, boom. So when you got less verbiage, it’s easier to remember. It’s kind of genius."

Delay of game penalties should definitely not be a problem. The Eagles no-huddle generally snapped the ball with about 15-20 seconds left on the play clock.

It's worth noting here that Celek's brother Brent was one of Chip Kelly's favorite players in Philadelphia, a tough-blocking tight end, so Garrett may have a jump start in understanding how the new system works. Back in April 2013, after only two days of practice, Brent Celek raved to a reporter:

"From a communications standpoint, it's going to change the league... It's something that I never even thought was possible in the NFL. ...I can't say that we're going to be super successful, but from a communications standpoint, it's insane. I think it's awesome."

New Niners guard Zane Beadles, who played some up tempo ball with the Broncos, was also impressed. He told Maiocco:

"When you’re playing fast and defenses don’t have time to line up and get their hand in the ground, it definitely gives you an advantage offensively."

Beadles did note that it can be tiring, though, a complaint that uncensored young Eagles tackle Lane Johnson made after Kelly left Philadelphia. Beadles said:

"Definitely, at times, you get a little winded and you get a little tired. We’re going to be in great shape, that’s for sure."

Kelly's teams just don't huddle, even in the four minute offense. (They prefer to line up and force the defense to declare a look, then run the clock down and sometimes change the call at the line.)

Plays are called in from the sideline, which simplifies the quarterback's job in a way that might benefit the team's unproven QBs. Nick Foles had a miracle year with Kelly in 2013, tying the NFL record for touchdowns in a game with seven against the Raiders, before coming back down to earth in 2014 and last year with the Rams.

Kelly's teams have used a variety of methods to signal in their plays, from the giant posterboards of his Oregon Duck days, to a hinged fan of multicolored plastic "blades" that was mailed in unsolicited by a fan who invented them for softball games. Back around 2010, whne Chip was still at Oregon, Bill Belichick flew him out to Boston three times to explain his one-word no huddle play calls-- and used the tactic to destroy Tim Tebow's Broncos in the 2011 playoffs.

Currently, though, Kelly relies on hand signals -- not just one for the quarterback, but separate signals sent to each position group by a variety of assistant coaches and interns. Like most of his innovations, he copied this from another football program, as he explained in his 2012 lecture at Nike's Coach of the Year clinic:

"Boards and flip cards are an option. You control them, but they lack flexibility and they are awkward. Pictures are a method. One picture is worth a thousand words. The problem is they must be big enough, and how many boards can you have? It takes people to use them, and it is awkward. At the University of Missouri, the entire coaching staff signals their position players. All the signals are different and mean different things. They are hard to steal. The problem is practicing them in practice. All the coaches have to be on the sideline when you practice signals. It is an interesting way to do it, and we have studied them all, trying to find what is best for us. Our players make up our calls and codes. They choose things that make sense to them. The coaches may be totally out of touch with what they know and associate to their situations. You want them to choose things they can remember. What makes sense to you as the coach may not make sense to them. Information is the reduction of uncertainty. The players must all speak the same language and understand it. You want all your players on the same page."

The different calls for different groups adds to the difficulty of deciphering them. Sometimes you might not even want to know what something means.

There are real concerns though about intercepting signals. Last year, several players called the Eagles offense predictable, which is not the same thing as saying they knew the signals. It's also possible, as I've argued before, that the stripped-down playbook -- combined with injuries, OL and RB weakness, and Chip's aggressive purging of bad attitude players -- reduced the number of chess pieces he had left to the point where he was easy to anticipate.

But we know that at least one defender clearly deciphered Chip's signals back in 2014, because it was the Niners Antoine Bethea. As SFGate's Eric Branch wrote at the time:

"...early in the fourth quarter. Quarterback Nick Foles surveyed the defense and called an audible by motioning with his hands over his helmet. In response, Bethea began pointing to his right and yelling: "Hey! Hey! Run! Run! Run! Run!" The result: Defensive tackle Demarcus Dobbs drilled running back LeSean McCoy for a four-yard loss on a sweep left. Earlier in the game, Bethea had told his teammates on the sideline a run was coming when Foles made a back-and-forth motion over his helmet, a tip that earned him an approving slap on the shoulder pad from defensive line coach Jim Tomsula."

Chip's coaching in the NFL's toughest defensive division now, and the tempo might give his offense an edge in keeping them off balance. But his opponents include some pretty sharp guys, such as Richard Sherman, who will obviously be studying these signals in an attempt to break the code. Hopefully the coach can sit down with Bethea and work out ways to make them impenetrable.