Bamora!(2009)

Bamora!

At school, Kamazaki feels as though there is a circle drawn around her, a line that no one will cross. Part of it is because her face looks mean, part of it is because she's pretty socially awkward, and a large part of it is that she has earned a reputation for being really bad-tempered and violent to the people around her. However, this all changes in her second year of high school, when the cute, friendly, and popular Kume Asami crosses that invisible line and decides to be her friend. Kume introduces "Kama-chan" to friendship and to the 5-man soccer club that meets on the school roof. As Kama cautiously enters Kume's club, she may find herself able to grow past the bad expectations people have of her, and enter into a new, happier, high school life.

(Source: MangaHelpers)