I get the impression that his teammates have already begun to refer to him as Bazooka Joe, so they will have the final word.
Personally, I believe that moniker does not do justice to the strength of Joe's throwing arm. Carl Furillo, an outfielder for the Dodgers in the 1940s and '50s, was known as the "Reading Rifle" in tribute to his powerful throwing arm and the fact that he originally signed with a Reading, Pennsylvania minor league team. To update Milton's "weapons platform" designation, his arm strength reminds me more of a missile launcher, perhaps even an ICBM or surface-to-air missile (SAM), so SAM site Joe could work ... even if nobody else would ever use it.