The brief scuffle at Packers practice turned heads in the crowd. The dropped ball by a receiver during an offense vs. defense security drill drew roars from defenders.

The team has grinded through offseason workouts with a work ethic that coach Mike McCarthy says is one of the best he's seen during his nine years as head coach in Green Bay. The energy is up.

''I'm not saying the other groups weren't mature,'' McCarthy said. ''It just seems like this group is further ahead than we've been, and you can sense the energy.''

Caveat: It's June, still more than six weeks from the start of training camp and three months from the start of the 2014 season. Almost every team feels good this time of year.

The Packers, of course, have a championship pedigree. Confidence that comes with winning three straight NFC North titles, and just a few seasons removed from winning the Super Bowl.

''The work ethic is very high. This group is really extremely competitive, in tune. Our new training environment has been unbelievable. It has put us so far ahead of where we've ever been, so I think with that brings more confidence so there's just a sense of maturity,'' McCarthy said.

Changes on the coaching staff brought some new perspective. Quarterbacks coach Ben McAdoo left to become the offensive coordinator of the New York Giants, while outside linebackers coach Kevin Greene left to spend more time with family.

Sam Gash is the new running backs coach after Alex Van Pelt slid over to replace McAdoo. Winston Moss is the assistant in charge of all linebackers now, not just inside linebackers. Former Illinois and Florida head coach Ron Zook is now an assistant special teams coach.

Green Bay hopes the defense will be improved this year with the addition of Julius Peppers and the anticipated healthy return of linebacker Clay Matthews from an injured thumb. Eddie Lacy has a full year of seasoning now as the lead rusher in a talented backfield that complements Rodgers.

The 2011 NFL MVP, for one, likes the spunk he's seen on the practice field.

''I love it. I love the energy, I love the passion. There will be those altercations in training camp. When guys remember this is a professional environment, not a personal environment, then you won't have any issues in the locker room,'' Rodgers said. ''But every now and then you have to stir it up a little bit, you have to make some changes.''

Rodgers said he also likes the changes he has seen with new personnel and new coaches.

''It's a natural progression. And when you have some new players there's always going to be stuff like that, guys getting used to this tempo,'' Rodgers said. ''Sometimes guys don't like getting tossed down a little bit, and you need to work it out.''

Fringe players anxiously looking for a roster spot shouldn't get too overly worked up. Jobs aren't won in June, McCarthy said, when practices are tailored to highlight agility and playing in space.

But McCarthy likes some of the intangibles that he has seen so far.

''I think you're seeing more player interaction as far as what goes on on the field. Guys self-correcting, and a lot more pro-active as far as sharing information,'' he said. ''Those are good things. I see more of it this year.''

Note: The Packers signed rookie free agent Shaun Lewis on Tuesday. Lewis, a 5-foot-11 linebacker from Oklahoma State, tried out at Packers rookie minicamp in May. He had 73 tackles and three interceptions last season for the Cowboys.

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