When I'm configuring my minor league rosters, I have several players that I want to develop.  My ML team is in the National League, so no DH.  I have a bunch of AA, AAA prospects who are fantastic hitters, but relatively poor fielders.  When they get to the majors, I'll need them to play either LF or 1B.  If I put them at DH, or 1B or LF in AA or AAA will they develop differently defensively?   Will the DH not get any better at defense?  That makes sense logically to me.  Will the LF develop more range perhaps than the 1B?  

Also, this question could be applied to platooning hitters.  If I platoon players vs. L/R, will their splits get more extreme?  For example, I have a 24 y/o and 25 y/o CF pair that I will be plattooning in CF.  One has a more even split, and shows some projected improvement where he could possibly be an everyday starter.  Will platooning him hurt his progress against Lefties?  Again, this make sense in real life, but not sure about how this game works.

The hitting splits won't change based on platooning. Recently someone posted which positions yield the best fielding development, finding that thread may be helpful.

From what I have heard SS, 2B, CF, 3B, LF, RF, 1B are the basic order for defensive development.

So if you do not have a SS prospect, you should put your best prospect at SS thus improved defensive development will occur.