While not yet fit to play, the midfielder will be in Braga to support his teammates.
Isco has been missing for four and a half months due to a leg fracture.
Isco told the Betis website: "I was eager to get back to the locker room atmosphere, be close to my teammates, keep improving, and regain my form.
"We're at a point in the season where we need to be more united than ever. The time has come when we're playing for the most important things, and I think it's time to be together; I really wanted to be close to the team."
He also said: "I'm improving. It's been a very difficult process, and I'm still experiencing some discomfort, but I'm finally seeing the light at the end of the tunnel, which I desperately needed.
"I'm eager to help the team from within, but since that's not possible yet, I'm contributing my bit in the locker room. I'm really looking forward to tomorrow's match and the rest of the season."