Amir Khan is shown in a April 21, 2018 photo. Former unified light-welterweight world champion Amir Khan has retired from boxing after a career that also included a silver medal at the 2004 Athens Olympics. The 35-year-old Khan said on social media that “It’s time to hang up my gloves." (Peter Byrne/PA Wire./PA via AP)

Amir Khan is shown in this April 16, 2011 photo. Former unified light-welterweight world champion Amir Khan has retired from boxing after a career that also included a silver medal at the 2004 Athens Olympics. The 35-year-old Khan said on social media that “It’s time to hang up my gloves." (Dave Thompson/PA via AP)