I don't know if it's safe to rate him just yet but as of right now, I'd give him something in the range of Bs.
Like others said, he did a great job not having to get rid of guys like Bard, Buchh, Bowden for V-Mart and suddenly, our C spot(if or when he plays there) might go from a hole in the lineup to a strong spot.
On the other hand, there's still the whole Krotch/Rochey deal(can't YET comment on that though) and the fact that we didn't get another arm. Our rotation has struggled and it hasn't gotten better.