If Conor McGregor REALLY offered to step in and fight Frankie Edgar at UFC 222 in March -- it's news to Frankie, who tells TMZ Sports he never heard Conor was throwing his hat in the ring.
As we previously reported ... Conor says he reached out to the UFC to replace Max Holloway in the March 3 main event after Holloway suffered an injury in early February.
Conor claims the UFC shut him down, saying there wasn't enough time to properly promote the fight.
Edgar has a new opponent -- Brian Ortega -- and tells TMZ Sports he's currently focused on beating his ass.
But if he gets through Ortega ... Edgar says he's MORE than happy to step in the Octagon with Conor -- if his offer was REAL.