Diamond no Kouzai

"I was meant to play baseball!" Jirou Ayasegawa has a natural gift for sports, but life can be lonely at the top. He's crushed other players' dreams. Some have even given up their sport altogether because of him. Eventually, he encounters "The Bambies," a low-level, local kids' baseball team that plays purely for fun. Jiro signs up, thinking that he's finally found an easy-going team to enjoy baseball with, until things take a sudden turn...

(Source: MANGA Plus)