This is a bit of a loaded topic. I consider it loaded, because the meaning of "Major League ready" has a definitive definition for each of you, and, for all practical purposes, your definition is no better or worse than any other. Nonetheless, Daniel Descalso has slumped, Addison Russell has baggage, and Nico Hoerner hasn't played a game since April. While Carlos Gonzalez has stretched the bench for the outfield, Garcia is the tempting option for the infield. Should Garcia get a call-=up before September?
I referenced different meanings of MLB-ready above. Your definition may be "will he produce at a (league average, perhaps) rate.