Springer was an elite OF in the minors... its not that he forgot or had to "learn" how to play major league RF... he was making dumb mistakes that likely had to do more with nerves than ability. Marisnick has thrown the ball where he wants to, with good speed, more often than not in his career... you're just anecdotally stuck on a few mishaps that will happen to ALL strong-arm outfielders from time to time.
Springer was a CF at UConn and most of he MiLB career, until his latter days at AAA. They are not the same position, different reads off the bat.
He was making r****ded/dumb errors... and he's been playing gold glove caliber RF since he got over those initial jitters. So, either RF is most definitely a "new" position to him and he's just the world's fastest adjuster... or he's had the ability to make those reads and he just needed to stop moving at 1000 MPH on every ball hit to him. Again... you're hung up on this. Just like you're hung up on Marisnick's occasional inacurrate throws. Melky Cabrerra just air-mailed a tailor-made throw at the plate... after nailing Altuve in the 1st. It happens...
I'm not hung up on anything and I have minimal ideas why this conversation digressed that way. I'm just stating observations of the games and players that I watch. Springer has gotten all-world better, Marisnick can and does need to improve his accuracy, sorry for pointing that out. They both have crazy talent.
Right now, Marisnick needs to work on hitting more than his "accuracy" issue that really isn't one.... perhaps that's an observation you could be making (although I don't think he will ever hit "bad" enough to not be in this lineup).
No pitcher does... human arms never meant to throw overhand. What Neshek is doing is carnival/circus-trick stuff... like he's got a rubber arm.