He showed in the NHL this year that he's basically not really ready for the NHL.
2C- Not good enough offensively. His assists are kind of a mirage, he didn't really do anything to create the eventual goals. His own goals were all scored around the net. He's an average skater, has a very bad shot and hasn't shown much playmaking ability. I didn't watch him in Sweden so I can't say if he was more of a playmaker over there but he certainly didn't wow me on NA ice.
3C/4C- He has above average defensive positioning and awareness and certainly works hard (he'll go to the dirty areas and give it his best) but the problem is that he is just nowhere near physically ready for the NHL. When he goes to the boards he gets knocked down all the time. Also, he's not good on faceoffs. A small guy who doesn't hit, win faceoffs or board battles is not exactly a great fit as a bottom line center.
So his first season in NA makes me wonder where his future is, if the Hawks had any real center depth Kruger wouldn't have been in the lineup last year or this coming year. Ultimately I don't think he'll be a center in the NHL, I see him more as a 3rd line winger. He needs to get bigger though otherwise he'll have a very short career (both in regards to his game and his health, he already has had a concussion that kept him out). He could have an outside shot a being a 3rd line center but he'll have to work hard to improve not just his strength but actually get bigger too so he can handle the toughness of the NHL.