How much of prospects being promoted involves outside factors?

[BrewCrew8675309]

I was wondering if the Timber Rattler players who are doing well were being held in high A because once they get promoted no ones resdy to fill their roster spot on Wisconsin. To what extent does this go into timing of a promotion? I know Big League teams like to promote players into a homestead rather than on the road... so there are some outside factors that go into promotions. Jett may be being held back because they want to avoid Super 2 designation, but he also might be being held back because his split vs RHP is sub-optimal.