LAKE FOREST, Ill. -- Chicago Bears defensive end Shea McClellin packed on five to seven pounds of muscle, and shed fat in the offseason, knowing that in "Year 2, I need to take a big step," he said.

For right now, any strides he expects to make will come from the defensive end position.

"I'm playing d-end," McClellin said when asked if he'd be asked to switch positions. "That's what I'm going to be doing. You never know, you could be doing something else (in the future)."

The club's first-round pick in 2012, McClellin put together a solid, but not spectacular rookie campaign after struggling during the early part of training camp. McClellin finished his rookie season with seven tackles in 14 games, in addition to 2.5 sacks.

Of the 369 snaps McClellin participated in, he spent 268 of them rushing the passer, playing mostly as a sub package contributor. McClellin finished the season with 29 quarterback pressures.

"You see it on tape. He's athletic. He's got pass-rush ability," Bears defensive coordinator Mel Tucker said. "He's very conscientious about getting better each and every day. That's what I was told about him. I saw the ability on tape, and out here on the practice field."

Whether that transfers into games remains in question. Tucker declined to get into specifics when asked about McClellin's potential role in 2013, saying only that "he'll get what he earns. So we'll see."

McClellin, meanwhile, plans to prepare for an increased role. Without the team asking, McClellin worked to add bulk and cut fat, a process he plans to continue throughout the summer before training camp. He's also working to increase speed and quickness, and wants to learn to utilize his hands better as a pass rusher.

"I knew I had to get bigger. That's what one of my goals was. I lost some fat too. That was my goal, to put on more mass and lose some percentage in fat," McClellin said. "That's what I did. I'm gonna continue to work on that this summer, too before training camp. I need to keep continuing to work on my pass rush and get better at that, (work at improving) at the point of attack, getting off (the line of scrimmage), just little things that I can get better at. I'm working my hands a lot more than I did last year."

That's what general manager Phil Emery expects. McClellin's conscientious efforts to continually improve are a part of the non-physical attributes that drew Emery to the defensive end. In discussing McClellin and 2012 second-round pick Alshon Jeffery, Emery said he needs both to "be better and contribute at a higher level" in 2013 because "that is the criterion for evaluating players towards winning championships: Is that player contributing at a high level, and is he continuing to improve?"

McClellin worked with the first team at defensive end opposite Julius Peppers, but it's unknown whether he'll remain the starter there in the regular season. It appears the staff has developed enough faith in McClellin to at least give him a legitimate opportunity to win the starting job.

"Whatever I can do to help the team, that's what I'm gonna do," he said. "If they want me to play more, I'll play more."