If Springer is brought up it'll be an incredible turn of events.  

Springer is as much of a known quantity as the minor leagues can show.  I have no doubt he's a sure thing for the Astros next year.  For that reason there's no real need for the Astros organization to make a roster change to evaluate him over 2 weeks of play that will likely often be against other callups to end the season.  Once he's on the 40-man roster that would tie up that slot and prohibit another player from being exempt from the Rule 5 draft.  I just don't see them bringing up any player at this point who is not already on the 40-man roster and not susceptible to the draft.