...all I remember is that it at the start, the main experienced high(?) school player teaches a kid who knows nothing about is the one to make the team while the experienced player is relegated to reserves. Unfortunately, that is all I remember at the moment.

Any help is greatly appreciated.

Not changing this sig until Square-Enix & Namco-Bandai collaborate to produce a "Tales of..." game (Feb 8, 2008).

Something near that happens in Slam Dunk. Though I think you would have recalled if that was it.

wow, this is a really old post but I think you're talking about Fight No Akatsuki.

"Akatsuki and his good friend Kiyoharu (whom Akatsuki calls Kiyo-chan) have been playing one-on-one basketball for quite sometime. Unfortunately, things started to change after they joined a very strong basketball team in their new school. Both of them were forced to separate into two groups: Kiyoharu was in the "B" group, and poor Akatsuki was put under "F" group, which is known as the "Failure" group. However, Akatsuki was not discouraged at all. He continues to train hard and always has a smile on his face. Will Akatsuki succeed in his promise to Kiyoharu to become an official player? And what is blocking the path to his goal?" (mangaupdates)