Re: So now ... pick two
Mays is one who HAS to go. I don't think Standridge can be sent down, because he was already removed off the 40-man this spring due to no options remaining and they had to add him back when he last came up. I'd much rather Standridge than Yan at this point. There's a chance Weathers is just injured, otherwise he went from decently-kinda-serviceable to AWFUL almost literally overnight several weeks ago.
If this scenario has, say, Yan and Mays being DFA'd, then Belisle would probably at least temporarily be the fifth starter when they need one. That would still leave Standridge, Mercker, Weathers, Coffey, Guardado and the two new acquisitions, Bray and Majewski as the seven-man pen.