ANSWER:

The most authentic opinion is that the navel and knees are not part of the awrah, rather the area between the navel and the kness is awrah for a man. 

Thighs are part of the awrah and he cannot expose this in front of anyone except his wife.

Is the navel and the knee included in the awarah for men and can men wear football shorts in front of other men where his thighs are exposed?