@Gregtito Could a Sorcerer use Subtle Spell metamagic to cast while polymorphed, assuming the spell only requires V and/or S and not M?
— Thom Bly (@thomBLY) August 3, 2017
The polymorph spell prevents a transformed creature from casting spells. #DnD https://t.co/k7y5VqpqgM
— Jeremy Crawford (@JeremyECrawford) August 3, 2017
“Unless its new form allows it.” I would say that the problem here is that Spellcasting is a Class Feature and is lost during Polymorph.