GREEN BAY – The gap is starting to close, but it's just starting.

Head Coach Mike McCarthy often talks about the gap between young players and veterans on his football team – their awareness, knowledge, play speed and the like – and he's always monitoring how big it is.

The sooner it closes, the better off the Packers are each and every year, and with one preseason game in the books, the process of closing it is underway.

"It's vital to the success of our football team getting ready for Chicago," McCarthy said on Friday, referring to the regular-season opener coming up on Sept. 9.

Speeding up that process is one reason, aside from reducing injury risk, that young players get the bulk of the work in the preseason while many veterans play sparingly, if at all.

As usual, that was the case Thursday night at Lambeau Field in the 31-17 victory over Tennessee, with more than a handful of relatively healthy starters resting.

As the players reviewed the game film on Friday, McCarthy said the interaction between the young players and vets was evident, with a lot of conversations going on that should set up the team's youth to make more progress in the second game this coming week against Pittsburgh.

"I'm pleased with the progress we made from the practice field to live action for the first time, but we haven't accomplished anything yet," McCarthy said. "We aren't where we need to be."

One example McCarthy pointed to was with the wide receivers. While Marquez Valdes-Scantling, Jake Kumerow and Equanimeous St. Brown all had standout moments, combining for 12 catches, 238 yards and two TDs, there's plenty more to do to get ready for the regular season.

McCarthy praised the job the young receivers did getting off the line of scrimmage, but their moves weren't as crisp at the top of their routes.

"We need live reps," he said.

Another example was on special teams, where McCarthy said some players were "trying to be too correct instead of cutting it loose," so an emphasis this coming week will be further establish the style of play he's looking for. On kickoff returns, for instance, the unit couldn't break Valdes-Scantling loose on his three attempts, and it covered well until allowing a 64-yard runback late in the fourth quarter.

Defensively, McCarthy thought the first live tackling of the summer was "pretty good," but there's always more focus needed on fundamentals. One missed tackle early led to a 38-yard gain for the Titans, but otherwise explosive plays were kept to a minimum.

"We have a ton of work to do," he said. "There's a number of things we need to get better at.

"As far as finish and putting it all together, we've played one preseason game, and that was clearly reflected by the video."