“If (player) could only _____ a little bit, then the (team) would really have something.”— Ancient baseball proverbWhat if Hard Throwing Pitcher could throw strikes, even at a slightly below-average rate instead of well below average? He’d get Cy Young votes, if not the actual award. If Superlative Defensive Catcher could hit .280, my goodness, he’d be worth a nine-figure contract extension. On and on it goes, throughout the roster and defensive spectrum. If a bench player could hit righties just fine instead of only hitting lefties. If only a slow player were fast, or if a clankmitt could field. If only this DH with a 1.000 OPS also had an ERA under 1.00.You get the idea. It’s easy to dream, hard to actualize. We are all eternally “the ability to play violin” away from the New York Philharmonic, and it isn’t too different for toolsy baseball players.Except some of those dreams can actually come true. If Kevin Pillar could hit even just a little bit, he’d have a 13-year major-league career. If Randy Rodríguez could throw strikes, he’d be a dominant closer. If Casey Schmitt could stop swinging at everything and start swinging at only most of the things, he’d be an everyday player. It’s a fine line between magical thinking and player development.This brings us to Jonah Cox, the latest Giants position-player prospect to make the majors. While he’s made a couple of plays, we haven’t yet had an opportunity to see him blaze across the vast expanses of the Oracle Park outfield. He’s scored a couple of runs, but we’ve seen his speed only briefly: