The Britain star will take on Vargas in Birmingham in an attempt to get a world title fight before the year ends.
Khan had destroyed Phil Lo Freco in 39 seconds when he returned to fight in April after a gap of two years.
Speaking during the announcement of the bout, Khan said: “One of my aims this year was to be as active as possible so I’m very happy to get back in the ring again so soon against Samuel Vargas.
“Vargas is a tough and well-schooled fighter who has shared the ring with some top welterweights including Danny Garcia and Errol Spence Jr.
Vargas ended up with him on the wrong end of a knockout against both Gracia and Spence.
— Amir Khan (@amirkingkhan) June 28, 2018
“I have to get past Vargas before looking at the biggest challenges going forward. I’m not going to be taking Vargas lightly because I know he will be coming with everything on September 8.”
Meanwhile Vargas’ last fight had ended in a draw with Mauro Godoy in February and he has promised to give Khan a better fight than Lo Greco.
“I have been granted more than enough time to properly prepare for Amir and you will see the best Samuel Vargas to date,” said the 29-year old.
“Mark my words, we might both be from the same city and county but I am nothing like Phil Lo Greco that’s a guarantee – I’m going to give Amir hell.”
Anthony Joshua has been given a 24-hour deadline to sign to fight Russian Alexander Povetkin or face being stripped of a portion of his world heavyweight title.
Joshua’s promoter Eddie Hearn has been negotiating for a unification bout with WBC titlist Deontay Wilder but the WBA has lost patience and wants him to face its own mandatory challenger.
WBA president Gilberto Mendoza said in a statement: “Today the WBA requested an answer from Anthony Joshua’s team regarding his fight with the mandatory challenger Alexander Povetkin.
“The WBA have allowed over a month extension to negotiations with Povetkin and also ongoing discussions with Deontay Wilder.
“It appears the Wilder team have not returned the contract for the fight and therefore we are requesting a date for the Joshua versus Povetkin fight with immediate effect.”
The demand will not cause Joshua’s team too many issues given negotiations with the Wilder camp appear to be deadlocked and former champion
Povetkin represents the next-best bet for a stadium-filling autumn bout.
Joshua’s promoter Eddie Hearn had indicated he was close to agreeing a deal with Wilder, but the American’s team claim to be holding out for “clarifications”.
Povetkin, who held the WBA’s ‘regular’ title between 2011 and 2013, beat Briton David Price in his last fight in March on the undercard of Joshua’s win over Joseph Parker in Cardiff.
The Principality Stadium would be favourite to host the prospective contest between Joshua and Povetkin, confirmation of which would delay a clash with Wilder until at least next year.
British boxer Amir Khan launched the Super Boxing League in Pakistan with a host of cricket bigwigs part of the new venture.
According to a report in The Dawn, Khan is promoting the event that is being backed by British businessman Bill Dosanjh.
Khan will be the league’s chairman along with Salman Iqbal – CEO of ARY Digital Network and owner of PSL franchise Karachi Kings. The league will feature eight teams owned by cricket stars and and showbiz celebrities.
Former Pakistan all-rounder Shahid Afridi announced he is the owner of Pakhtoon Warriors, while legendary pacer Wasim Akram leads the Multan Nawabs.
According to the report, the eight teams will represent Pakistan cities of Karachi, Lahore, Islamabad, Peshawar, Faisalabad, Multan, Sialkot and Quetta.
The SBL is being organised in association with the World Boxing Council and is scheduled to be held from September 28 to November 3 at the Amir Khan Boxing Academy in Islamabad.