Not to beat a dead horse, but... through 15 starts this year, Oliver Perez and John Maine have done the following:
73 IP (4.9 IP/GS), 83 H, 53 R, 49 ER, 13 HR, 52 BB, 66 K, 6.12 ERA, 5.84 FIP
This was not outside of the realm of possibility in the spring; in fact, many people on this site (and elsewhere) discussed it for the better part of the month of March. This is why it made sense to keep a bunch of guys who could slot into the rotation.
Fully 41% of Met games this year have been started by two pitchers who have been sub-replacement level. The Mets are 4-11 in those games.