Ginrei Kuchiki  

, 朽木 銀嶺,

The character you're referring to is likely Captain Yamamoto from the Gotei 13. He wears a scarf similar to Byakuya, but doesn't have an aristocratic hairpiece like him. According to the Turn Back the Pendulum Miniseries, he was one of the first Captains in the Gotei 13 and resembles Captain Yamamoto-Genryūsai from later years. However, it is unlikely that he is still alive since only a few old captains remain, including Shigekuni Yamamoto-Genryūsai, Retsu Unohana, Jūshirō Ukitake, and Shunsui Kyōraku. In the Turn Back the Pendulum Miniseries, he introduced Yoruichi Shihōin to Byakuya, who was training at the time. He also seemed frustrated with Byakuyas impulsive behavior, suggesting that he would make a great leader if only he learned to control himself, which he did in later years. It's unclear whether or not this character is still alive during the present storyline.