Well, that being the case...
It is not that the company does not need cash (they do), rather they really need flexibility around the strict covenants with the ATSB. Applying proceeds from an asset sale directly towards our our balance might buy that needed time/breathing room.
I would not discount the additional possibility of Piedmont, and even Midatlantic also being on the block. Piedmont's aircraft and flying would again be a good match into Mesa Air Group. (esp with the new found interest in Florida).
Not so sure about MDA though, it seems to be the least likely of the three possible asset sales, as MDA serves as a bargaining tool/form of leverage with mainline labor where PSA and PDT do not. And MDA is still directly part of the Mainline, without a separate certificate at the moment (while PSA and PDT are turnkey and ready fit operations). There is no doubt that MDA could be spun off and sold as well, and it might very well be, but IMHO it is the least likely of the three to do so.
But back to PSA, it does seem to be a much more attractive item to sell now that the 328's are about gone, and the bases/mnx are consolidated. PDT as well has been completing the consolidation of ALG, recently closing some bases, and parking unwanted aircraft..., so it too has become a much more attractive asset for sale.
Like I said, just speculation