SAYONARA GAME

Arimura enlists the help of Yosuke—a younger baseball club teammate from his high school days—to tutor his little sister. Yosuke has always been rather brusque around Arimura, but to the older man’s surprise, he discovers Yosuke actually looks up to him. But could Yosuke’s admiration be masking something more? (Source: SuBLime) — Description from AniList community (anilist.co).