Meimon! Daisan Yakyuubu

Asunaro is a new student at a school with three baseball teams; the first is renowned as being one of the best in the prefecture, but the third, Asunaro’s team, is filled with the rejects and unskilled of the baseball world. As the baseball instructor deems them to be nothing but trash, he informs the team that they will be disbanded in one month – that is, until one of the players begs him to let them play a single game. They’ll be up against the first team, and if they win, they’ll get to take over the title and even work their way towards playing at Koshien Stadium. With the help of Kaido, an ex-member of the first team, Asunaro and his friends will do whatever it takes to show they’re more than meets the eye!

(Source: Anime-Planet)

Note: Includes 4 extra chapters.