WWE has many former superstars the can bring into the Performance Center. It seems that Santino Marella is doing just that.
Marella announced during an Impact Wrestling Twitch stream that he plans on going to the WWE Performance Center as a guest coach. He will be a coach there till March 27th.
Marella has been keeping himself busy by focusing on running his Battle Arts Academy. This mixture of MMA and pro wrestling is certainly something the Performance Center would benefit from as they prefer having a diverse range in the kinds of talents they can teach.
Perhaps WWE might bring Marella back as a full-time employee if all goes well. He could definitely teach people how to hone their in-ring skills and also improve their character work.