Free kick yes, shouldn't be a red as it wasn't a deliberate attempt to stop a goal scoring chance. Unless you think Redmond pulled him down on purpose, looks like he accidentally does.
He clearly grabs his arm early on in the run to try to stop him running free on goal. That's what I would have given the free-kick for, and for me that was a deliberate attempt to prevent a goal-scoring opportunity. I'm not totally convinced the bit in the box where they both go down is even a foul tbh.