sasuke no have yellow power sphere
Did you notice how the robed figure was leaning far back into that projectile? There was a tense posturing of the body on their right side with their left half hanging downward in an almost gangling manner - it's as if they were intentionally applying little to no energy or pressure to hold that part of themselves up. The physically dominant half of their body seems to be on the right.
If that's indeed Sasuke, he might not have replaced his destroyed arm after all. Most shinobi can't formulate handseals without two hands, and close to all of the arsenal of elemental jutsu that Sasuke knew relied on seals. Assuming he didn't learn how to cast jutsu with one-handed seals like Haku and Minato, Sasuke would need to replenish his basic moveset with some fresh techniques that don't require any seals.
How interesting would it be if that sphere in his hand was actually a Rasengan created by Sasuke? He suffers a life altering injury to his body as a result of his dark ambitions and now since much of his base power has been stripped of him, Sasuke is compelled to turn towards Naruto for help. The Chidori was originally the product of Kakashi's failed efforts to apply Raiton to Rasengan. The fundamentals were inspired by Rasengan. Could it be that Sasuke managed to succeed where Kakashi failed? The concept of a lightning based Rasengan already existed. To see Sasuke relying on the powers and ideas of people he once spurned would be one of the greatest ironies of the manga.