Genius Batter Tezuka-kun [Ace of Diamond]

Blurb:

Tezuka Kunimitsu is the captain of Seigaku's tennis team.

In his third year of junior high, he and his Seigaku teammates win the national tournament. As they prepare for the upcoming world tournament, Tezuka Kunimitsu realizes that he has arrived in another world.

There, Tezuka meets someone very much like himself.

That person is Chris.

To return to his original world, Tezuka throws himself into a series of efforts. At first he knows nothing about baseball, but eventually he can throw a diagonal slider and a forkball.

Tezuka: Why does a batter need to practice pitching?

Later, Tezuka Kunimitsu finally completes his mission, but the two worlds inexplicably merge. Tezuka becomes a professional player who plays both baseball and tennis.

Tezuka: Huh?

Oishi: Tezuka, don't give up tennis after you start high school.

Chris: Kunimitsu, don't give up baseball. You're better suited to it.

Tezuka: ?

Tezuka thinks he must be dreaming. Otherwise, how could their three years together have turned into just one month of summer vacation?

But why does Chris call him Kunimitsu?

A crack pairing. I'll start writing once it gets over 300 bookmarks

Theme: Is there something wrong with Tezuka playing baseball at Seido?