Captain America

Leeroy's surname is Rogers, just as Captain America's / Steve's. His teammates have noticed it - and sometimes laugh at him calling him 'Captain RoyRoy'.

I think the shirt might be a gift from one of them. I still don't think Leeroy would wear it, but still. Used it as an excuse to draw him a sexy nerd.  

Twin pic ---> 

Leeroy Rogers (c) me and dream_more_sleep_less

Captain America (c) Marvel