See Kilseq Rower (Not Mine)

This gets into traditional blue transmutation territory, just giving the creature a white bend.

Mmm, on the flip side; white gets flat out "Exile you" so this is that with a downside. I can see it, though it's a bit of a bend. But maybe it needs "Exile until" style downside?

Then it's just Lignify (which is not really a green card)

Exiling a creature and giving something back in return has been a white staple since Swords to Plowshares. The issue with it and Path to Exile etc. always has been that white got to efficient versions of this effect and skewed the color pie in eternal formats.

A less efficient three mana Crib Swap-variant, especially a sorcery, is not an issue compared to that and an appropriate uncommon.

I feel a calcified creature shouldn't be a "Golem", but otherwise this is fine.

EDIT: I feel, btw, Lignify is more blue than white, but not really inappropriate in either color.