U-31: All You Need Is Football!

The manga follows Atsuhiko Kouno, a soccer player who represented Japan in the 1996 Atlanta Olympics and had high expectations to become a star player. Now in 2002, he is 31 and has somehow slipped into obscurity. One day, he receives a notice from his champion team that they are canceling his contract. Atsuhiko is offered a new contract for his former team JEM Chiba, and it is there that he wagers his comeback. However, he's known on his new team as the "former Japan representative," and his young teammates make fun of him and treat him coldly because he's still wearing the #10 jersey even though they think he's past his prime. Through all this, Atsuhiko silently continues to practice in hopes of making a comeback.

(Source: ANN)