Ryu I have to think will only make it as someone who can give length, if they don't want to bring along someone like Bowden Francis (speaking of relievers that have done way better than expected).
Manoah I think if he can have a few big starts in September has the potential to give you a big game, but I think in a short wildcard series, unless if he's truly dominant all Septmebee, not sure I would trust enough. If you make it past that round, he could be a good game 1 option for the DS.
Also certainly a chance that Green doesn't impress in his return, or even guys like Yimi or Richards could blow up for a few games down the stretch and be left off. You probably only fully trust the top 3-4 arms anyways, would love nothing more to see no need to pitch Garcia in a short series.