GREEN BAY, Wis. – The difference in the Green Bay Packers' special teams this season might be subtle, but Mason Crosby noticed it almost as soon as the offseason program began last month.

And it could help turn around the NFL's worst special-teams unit from last season.

With Ron Zook in charge after coach Mike McCarthy promoted him to replace the fired Shawn Slocum, there's a clear message to those who will be covering and returning kickoffs and punts this year.

"Let's be honest: There's only so many things you can do on special teams," Crosby said in an interview this week, which marked the veteran kicker's first comments since McCarthy fired Slocum on Jan. 30. "I think coach Zook is doing a good job trying to make that clear, saying we're going to simplify this. We're going to play fast. We're going to play very physical, and we're going to overwhelm teams with those things. He's going to demand it out of guys. You can tell whenever he picks people out and he'll make sure that he gets the most out of them. I saw that in him as the assistant last year."

On a personal level, Crosby said it was difficult to see Slocum go. No one was more supportive during his slump of 2012 than Slocum. So it was no surprise to hear Crosby say how hard it was to see his longtime coach go.

"I've been with him my whole time, and I had a great working relationship," Crosby said. "He was always such a support for me and always had my back. Change sometimes can be hard, but coach McCarthy makes the tough decisions."

Time after time when Crosby was in the midst of a streak in which he missed 12 of 24 field goals in 2012, when he finished with a career-low 63.6-percent conversion rate, Slocum spoke publicly in support of his kicker.

Crosby emerged from that to have his best season in 2013, when he made 89.2 percent of his field goals. He followed that with an 81.8-percent season last year, but he was one of the few highlights of a unit that ranked last in the NFL in the Dallas Morning News' annual special-teams rankings.

The change wasn't just difficult for Crosby. He knows how tough it was for McCarthy, whose relationship with Slocum went back to the late 1980s during their days as college assistants at Pitt.

"They're very close, and you got to give coach McCarthy a lot of credit for just really analyzing himself, the team, every aspect and making some of those tough calls this offseason," Crosby said. "Him giving up play calling, I'm sure that was a very tough call for him. But he's embracing the new role he's taken on as far being an overseer of all things."

Crosby, who is entering his ninth NFL season, will be playing for his third special-teams coach. Each time there was a change, however, it came from within. Slocum was the assistant special teams coach before he replaced Mike Stock, who coached Crosby in 2007 and 2008. Zook spent last year in that role under Slocum before he was promoted in February.

"When I heard they were releasing coach Slocum, my first hope was that coach Zook would be the guy so we're not starting completely fresh," Crosby said. "He was here for a year, and we got to know him and build a relationship. It's been solid so far. I like working with him."

With cornerback Jarrett Bush unsigned and not likely to return, no player has been around the Packers' special teams longer than Crosby. In fact, he said some veteran special-teamers sat in a meeting room recently and noticed the only ones remaining from the Super Bowl XLV special teams were the three specialists (Crosby, punter Tim Masthay and long snapper Brett Goode) along with fullback John Kuhn.

Of the core special-teams players from last season, gone are three of the top four contributors in terms of snaps played: Bush, linebacker Brad Jones and tight end Brandon Bostick. Receiver Jarrett Boykin and cornerback Davon House, who ranked eighth and ninth on that list, also are gone.

"We're going to have a lot of young guys," Crosby said. "I think that's going to be the biggest difference."