Christian McCaffrey admitted he’s an unlikely brand ambassador for a clothing company. “I used to not care at all about what I wore,” the Carolina Panthers running back told USA TODAY Sports. “I’d wear one of every color. My mom would even call me out. Once I got older, it became a way to express myself. I don’t think I’ll ever be expressing myself like Cam (Newton), but it is something I take pride in now.” McCaffrey was tapped last month as one of New Era’s latest brand ambassadors. The Buffalo-based hat maker has brought in his former NFL receiver father, Ed, for the rollout of the company’s Official NFL Sideline Collection that launches Monday. Each of the 32 teams will have unique home hats this season that reflect the decade each was founded as the NFL celebrates its 100th season. “They look great,” said Ed McCaffrey, who wore three different logos in his 13-season career. “The fashion now is nowhere near where it was when I played. "When I think of caps, I associate them with victory. You put one on when you’re taken out of the game (as a starter). You were winning and stood on the sideline as the clock ticked down. I was fortunate to be able to get that opportunity at the end of so many games in my career.” Ed McCaffrey, a three-time Super Bowl champion, retired at 35 in 2003 and acknowledged a lot changed before his son was drafted by the Panthers in 2017 – and not just fashion-wise. “I ate fast food early in my career because I didn’t really understand the role nutrition played,” Ed McCaffrey said. “Christian entered the league with the knowledge it took me five, six, seven years to get. I hung around the league long enough to learn how to take care of my body. Christian has surrounded himself with great people and he’s a hard worker. He’s a student of the game and takes a great pride in staying healthy.” That dedication this off-season didn’t go unnoticed as photos from the Panthers’ workouts in April hit social media, with many observers noting that McCaffrey appeared to have added some significant muscle since the end of the 2018 season. He told USA TODAY Sports that he’s roughly the same weight as last season (listed at 5-foot-11, 205) and he “didn’t do anything crazy special” to get jacked. “My body is in a good position right now,” McCaffrey said. “I haven’t gained more than a pound or two. My aim going into every off-season is to maximize my speed. It was a lot of hard work.” McCaffrey said minus the football-specific drills, he did linear training, which typically involves heavier weight training at lower reps with a couple days off between the muscle groups worked. It’s more of an old-school approach to weight training, but maybe not quite as much of a throwback as some of the hats in New Era’s new line. The caps for the Arizona Cardinals, Chicago Bears, Green Bay Packers and New York Giants – whose NFL lineage traces to the 1910s-1920s – are made of a wool fabric to simulate hats worn in the day. Teams founded in the 1970s like the Atlanta Falcons, Cincinnati Bengals and New Orleans Saints have trucker-style caps with a foam front and mesh backing. “We sat down with the league several months ago to talk about what we could do to commemorate the NFL’s 100th season,” said Ryan DiNunzio, New Era’s director of football and soccer. “We wanted to celebrate it in an authentic way, so we started to think about how we could separate the teams into decades.” DiNunzio said there were some initial discussions to use Zubaz – the zebra striped attire that had a brief run in the 1990s – before a color block approach was used for the most recent NFL entries like the Panthers and Houston Texans. “I gave a lot of that kind of gear to my family, like the Zubaz,” said Ed McCaffrey, who is the head football coach at Valor Christian High School in Highlands Ranch, Colorado. “I saved some stuff, but not the Zubaz.” Follow USA TODAY Sports' A.J. Perez on Twitter @byajperez . If you love talking football, we have the perfect spot for you. Join our Facebook Group, The Ruling Off the Field , to engage in friendly debate and conversation with fellow football fans and our NFL insiders.