Polymorph Can Swap a field Npc or not?

[lair]

Polymorph
:Swap a fielded Character with a non-Npc Character from that player's used Pile.

if i have a npc character in field, one other character in my used pile.
can i use a fielded npc to swap another character?

[dmrulesteam]

Polymorph
:Swap a fielded Character with a non-Npc Character from that player's used Pile.

if i have a npc character in field, one other character in my used pile.
can i use a fielded npc to swap another character?

Polymorph can swap out an NPC/Sidekick die for a Non-NPC character from the same player's Used Pile.

-The Dice Masters Rules Team