It appears that Dana White misspoke during the conference call to announce that Georges St-Pierre is relinquishing his UFC welterweight title. He announced that a bout between Johny Hendricks and Robbie Lawler will be for the vacant title at UFC 171, which is true. But he also said that it wouldn't be the main event. Well, he's taken that back. The original main event for the show has been moved to UFC 172 according to a tweet from the boss:
Sorry I misspoke on the conf call. Hendricks vs Lawler will be main event in Dallas and Jones vs Teixeira will headline UFC 172— Dana White (@danawhite) December 13, 2013
This is now the fourth card that has been linked to the Jon Jones vs. Glover Teixeira light heavyweight title fight. Jones cited injuries to bump back the fight from UFC 169 to UFC 170 to UFC 171, and now it's at UFC 172. The event is scheduled for April, but a firm date and location haven't been announced yet.
With this move, Hendricks/Lawler is now the main event of the Dallas show on March 15th. Quite a busy day in UFC news!