Twitter sleuth Superannuation earlier today spotted an opening on the BioShock team for a network programmer.
Irrational wants someone who has "shipped at least one commercial network-connected game title, preferably on a console" and "previous experience developing network backend support on a multi-console title with support for matchmaking, stat tracking and analysis, in-game push updates, etc."
Judging by that job description, if BioShock Infinite was to ship without multiplayer the successful applicant would likely have a very boring time of it.
Currently Infinite has no confirmed multiplayer elements. However, creator Ken Levine did admit to experimenting with some online modes back in 2010.
We've asked Irrational for comment and will update if it chooses to clarify.