"We're sorry but the planned Return to Ostagar downloadable content scheduled to launch on January 5th has been delayed for all platforms," the forum post reads. "We will update you as new information becomes available." And then there's a little "devil" emoticon, which seems to be Priestly's forum signature rather than a hint that the post is a joke. The fact that the delay applies to "all platforms" suggests that the content could arrive after the "later in January" release window named for PS3 before.
We expect that BioWare will release more details (as in, some details) about the delay during business hours -- or an official denial, if this turns out to be inaccurate. In either case, we're waiting to see if we're going to be waiting for the DLC.