The defender has spent the past two years with Real Salt Lake.
But when speaking amid protests about racial injustice in the United States, Onuoha admits that as a Black man he sometimes feels unsafe in the nation.
"I am comfortable but when it comes to any kind of brutality, if it's from the police, if they read me the wrong way then my life could be taken. I feel that every single day. It is not just me but everybody else as well," Onuoha told BBC Sport.
"I am not trying to be overly critical to the police, there are plenty of good police officers out there, but sometimes I feel like people put police on a pedestal and make them seem superhuman.
He added: "I never go out and feel 100 percent safe.
"In the UK, I am more comfortable because if something happens it probably will not be deadly – but over here because of their rights it is more common that altercations become deadly. I am always very aware of that whenever I go around anywhere."