On Wednesday, Ariel Helwani of ESPN.com reported Johnson would head to ONE while Askren would join UFC if the agreement can be finalized, with all parties hoping that will happen soon.
Mike Bohn of MMA Junkie showed a deal could be close by pointing out that Johnson has changed his Twitter bio.
Both fighters need to get released from their contracts in order to move because they have "multiple fights" left on their deals with their current organization, per Helwani.
The update comes after Askren wrote Monday on Twitter there was a 98 percent chance he'd fight in the UFC.
Askren owns an 18-0 career MMA record with one no contest. That undefeated streak includes a 15-0 mark across notable stints with Bellator and ONE since 2010.
The 34-year-old Wisconsin native announced his retirement from MMA after he defended the ONE welterweight title in November 2017, but he left the door open for a return under the right circumstances.
Meanwhile, Johnson lost the UFC Flyweight Championship to Henry Cejudo in August following 11 consecutive title defenses dating back to January 2013.
He received a medical suspension from the California State Athletic Commission after the loss because of a knee injury, per Steven Marrocco of MMA Junkie.
Helwani noted there are still "hurdles" before the swap could be confirmed and stated the potential debuts for the fighters in their new organizations haven't been "seriously discussed."
If completed, it would be the first major "trade" in MMA history.