The linebacker joined the Browns earlier this year after four seasons with divisional rivals the Baltimore Ravens.
The 27-year-old told the team's official website: "I think we're on the right track. The biggest thing I've seen is the effort is off the charts. People are working hard. Everybody's into it. It's just a good mentality right now.
"That'll take you a long ways. All the other stuff will fall into place. When camp starts, you'll know exactly where you're at as far as moving together as a defense or an offense. I think we're giving a lot of effort and preparing well.
"In this next month, it's just a matter of creating a mentality and a culture on the team, and that'll carry you into camp and you won't skip a beat. You get here and you can get right into the important things, instead of worrying about getting in shape and creating a family-type team."
Kruger recorded nine sacks for the Ravens in 2012.