Since a wood oven has such fast cook time, I precook my sausage. After dollying up the sausage with spices and stuff, I press it out in an iron skillet. Loosely cover it with parchment or foil and stick it the wood fired oven. About one beer later, it's done. One nice, big patty you break up accordingly.
However, if you use a very thin piece, I imagine raw would work just fine.