O'Donnell is a natural right back and far better than the other options we had in our team at the time. The fact we were able to pick him up on a short term deal when we were struggling to fill that slot was ideal.
He is definitely in the modern full back style, though, where it's more important for him to be a wing back with crossing than a full back with tackling.
Not my preference for a defender, but that's more the fault of the modern game than O'Donnell's. I'd much rather have a guy that tackles and covers first, but I seem to be in the minority with that view these days.