Harrison will now face Bobbi-Jo Dalziel, who was one of the original eight participants in the PFL lightweight season prior to her elimination ahead of the playoffs.
PFL officials confirmed the switch with MMA Fighting on Thursday.
Dalziel last competed in July when she suffered a first round submission loss to Larissa Pacheco, who moved onto the playoffs where she faces former Strikeforce champion Sarah Kaufman on the other side of the bracket in the semifinals.
Dalziel actually picked up a win over Fabian in her first fight of the PFL season before she was eliminated from contention due to the promotion’s point based system.
As for Harrison, she’s looking to move into the finals to compete for the $1 million grand prize up for grabs in the lightweight division.
Earlier on Thursday, Harrison inked a new long term contract extension to remain with the PFL beyond the current season.