It's no longer just a rumor -- DriveClub is officially delayed until "early 2014," as confirmed by Sony today. Sony's Shuhei Yoshida gave a perfectly reasonable explanation for the delay, noting, "We understand that the delay is disappointing news, but can assure you that the reason we have made this decision is to ensure that when Driveclub launches, it will realize the next-gen racing vision."
Contrast will be offered instead of DriveClub in the form of a PlayStation Plus bonus, so it's not a major loss for non-racing fans. Still, this has to hurt Sony a little bit, losing another major game at launch, as this news hits right after the delay for Watch Dogs -- a game that was hitting the PS4 (and other platforms) a week before the launch of the Xbox One.
DriveClub [PlayStation Blog]