It's quite rare that such groups of synonyms or quasi synonyms have perfect equivalents in other languages.
I'd say you're right : jeter is probably the closest to "to toss", but in some contexts, it could also be translated to lancer, balancer, larguer, etc.
Jeter is also used, in French, to mean "to throw away" (put in the trash), so, of course this meaning cannot be translated by "to toss" alone, unless we added much context to it.
He is going to pitch the ball was counted wrong. A baseball pitcher pitches the ball to the batter rather than throwing the ball to him. And while first baseman does not pitch the ball to the second baseman but rather throws it to him, unless there is a specific french verb meaning to throw a ball so someone can swing a bat or similar club in an attempt to hit it, then pitch should be accepted in this instance.
It is very unlikely that this sentence could be about baseball jargon as the French playing the game are rare (@12, 600 licensees for baseball + softball, vs 407,600 golf players and 1,052,000 tennis players). As a consequence, only the broader meaning of "to throw/toss/launch" has been retained.