I think that's something we project on closers, that they unravel, instead of just having a few bad nights or not making one pitch (more than one, in some cases, but if you don't have it you don't have it). I mean, Lidge never really unravelled. Williams either. They just pitched badly. Of course that closer personality of bravado and intimidation lends itself to such an interpretation when they fail.
And I admit I don't like the fact that Neris hasn't talked to the press both times. It shouldn't be any more of a big deal than a player taking an 0fer or making the last out at the plate.
I don't think it's anything you send him down for, he should be able to work on his confidence, pitch selection and mechanics with the major league pitching coach. Though if the problems continue I woudn't be surprised to see him on the 10-day DL eventually.