It is understood a deal has been agreed for the 25-year-old, who previously held the IBO and WBC super featherweight world titles, to challenge Hannah Rankin (12-5, three knockouts) for her IBO and WBA super welterweight belts.
That would represent a jump of four weight divisions in under a year for Harper (12-1-1, six knockouts) following her first career defeat in November.
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She made her comeback at lightweight with a points win in March and the plan had been for her to rebuild steadily and gain further experience in the ring before challenging at world level again.
But a source close to the fighter said of the opportunity presented: "It was just too hard to hold back.”
Doncaster’s Maxi Hughes is also set to defend his IBO lightweight title against Sheffield’s Kid Galahad on the same show, which is expected to be headlined by Leigh Wood in Nottingham on Saturday, September 24.
Rossington’s Hughes (25-5-2, five knockouts) would be making his second defence of the belt he won with victory over Jovanni Straffon last year.
Galahad trains at the world-famous Ingle Gym and is bidding to become the first-ever two-weight world champion from Sheffield.
He has not fought since losing the IBF featherweight title to Kiko Martinez at Sheffield Arena in November.
Coincidentally, that fight took place on the same bill as Harper’s loss to Alycia Baumgardner.
In an interview last month, Hughes said: “I’m well up for it. This will be good karma v bad karma, good v evil.
"He takes steroids and cheats and karma got him with Kiko. It would be nice to ‘Kiko’ him.”
Galahad tested positive for the banned substance stanozolol in September 2014 and served an 18-month ban.
His last fight saw him knocked out by Martinez in the sixth round.
On Hughes, Galahad (28-2, 17 knockouts), who will be stepping up two weight divisions, said: “I don’t think he’s exceptional at anything, he’s not on the same level as me.
"I have boxed higher calibre fighters than him and when we get in there it will show.”
The pair previously sparred ahead of Galahad’s 2013 fight against Jazza Dickens.
Hughes trains alongside Josh Warrington, who beat Galahad via split decision in 2019.