When Khalil Mack gets in his car Thursday and drives to the Napa Valley Marriott for the Raiders’ training camp, the defensive end is packing light.

Just some clothes and maybe his guitar to help him relax at night. Rookie roommate Greg Townsend Jr. has been given the list of mandatory snacks.

Most important, Mack’s not bringing any mental baggage, none of the accolades from last season or any of the expectations or hype for both him and the team this year.

“I’m still learning, just trying to get better” Mack said, taking a break from his workout at San Francisco’s Empower Gym on Monday. “That’s the key to all of this.”

Running back Latavius Murray now calls Mack “Slash,” after Mack became the first player in NFL history to earn first-team All-Pro honors at two positions in the same season (defensive end and outside linebacker). Mack, 25, finished with 15 sacks, one shy of the franchise record, and led all edge rushers in the NFL with 82 quarterback pressures and 54 run stops.

The “Slash” nickname is also appropriate because Mack thinks he was two players last season, and the one wearing No. 52 the first half of the season wasn’t all that great.

“I am very critical of myself,” Mack said. “Watching the tape of myself last year, it looked like two different players the first half of the season and the second half. This year, I want to start fast and finish strong.”

Mack thinks he overloaded himself the first eight games. He had only four sacks in that span, and would roll off 11 over the next six games.

“I switched it up too much the first part of the season, trying to show everything I worked on in the offseason,” Mack said. “All these moves and counters. … So mentally and physically, I made it simple. Just use speed and power and focus on two moves that I was having success with throughout the year. I was able to play faster and longer.”

To look at the sculpted physical specimen that Mack (6-foot-3, 255 pounds) is, one would miss what separates him and the league’s other great pass rushers: His motor doesn’t stop.

“Getting sacks is all effort,” Mack said. “Justin Tuck used to tell me that pass rushing is one of the luckiest things in the world. The quarterback can fall in your lap sometimes, and sometimes no matter what you do, you can’t quite get to them. But they all count.”

It’s seemingly rare in sports when a team’s best player is also the one grinding the most before, during and after practice. Defensive tackle Dan Williams says the Raiders are blessed.

“Khalil is such a hard worker,” Williams said. “You can’t put a ceiling on what he can do. … Khalil is going to be Khalil, and we all expect him to get more sacks this year. That’s kind of crazy when you think he had 15 last year. But he’s ready to take over the league.”

Mack tunes out compliments, whether it’s from a teammate or a talking head on TV saying the Raiders are going to go from 7-9 to winning the AFC West.

“You hear all different kind of things,” Mack said. “I like to focus on the negatives. Negative things tend to help me grind a lot harder. I don’t like positive stuff too much. … Not even in my relationships. Man, I don’t want to hear how great things are going from anybody.”

That wasn’t a problem with Mack’s mentor, Tuck. He is retired now, as is safety Charles Woodson, but they groomed Mack to take over the leadership role on the defense, if not the whole team, this season.

Said Mack: “It’s just about being a team player right now, getting everybody on the same page so we can accomplish what we want to. We have the talent, and with a positive mind-set and hard work, anything is possible.”

It’s one of the reasons that he is looking forward to training camp — because of how the team clicked last year and how well the new players have fit in. Big free-agent signings Kelechi Osemele, Bruce Irvin and Sean Smith haven’t needed a transition period.

“What excites me the most is that we’ve put together a great group of guys,” Mack said. “Not only the players, but the coaches. I am excited to work with all the new cats.”

Mack knows he will be a marked man this season, with opposing coaches spending the week before games against Oakland scheming to double-team and erase him.

“You have to welcome the challenge,” Mack said. “But at the same time, being a leader on the team, you have to let the other guys know, ‘Hey it’s not just me on this side of the ball.’ We got big Bruce, I got Rio (Mario Edwards), I got Big Dan, Big Jelly (Justin Ellis) … We got 27 (Reggie Nelson), DA (David Amerson) and Big Sean on the back end …

“We got some playmakers and heavy hitters. We’re going to make some noise. … They say you can’t win them all, but we’re gonna try.”

Vic Tafur is a San Francisco Chronicle staff writer. Email: vtafur@sfchronicle.com Twitter: @VicTafur