I wouldn't think so to be honest. All the recent acquisitions of Zenimax (the company that owns Bethesda) have been smaller studios with no past history with the mmo space. Beyond that, Bethesda has not ever really even worked within the framework of producing a multiplayer game much less one that works on a massive scale. Moreover, there have been no announcements in the last year or so of job openings that imply a shift in that direction (i.e. explicitly looking for MMO experience or even network programmers).
Thus, with no past history in the subject, no major acquisitions in the field, no recent job postings on the subject and no announcement to the effect, I'd be willing to bet that it won't, in fact, be an MMO. I'd even go so far as to expect that the game isn't even multiplayer capable.