I was scanning for him in the first battle, but once I heard his voice at the seige of Mandalore, goosebumps and a squeal of joy. Also, seeing Anakin's sabre movements showing flashes of his Vader era style with those push offs was epic.
He was also standing and talking with the fighters in the near background when Anakin was talking to Ahsoka after she was mourning the deaths of the clones.
They used his voice in this episode. Maybe it was a clip of something he said when filming the prequels, but it’s definitely his voice. Maybe they’ll tease him at the end of the season.