Barca's new boss, who was making his away league debut, is said to have reacted over-the-top and, according to the referee's match report, was punished for "angrily protesting a passage of play, having been warned by the fourth official".
Vilanova reacted to the decision by telling a post-match news conference: "The expulsion was excessive because I didn't say anything that was out of line.
"I told the linesman that it was a clear foul and he told me not to protest.
"It seems that this is enough to get you booted from a game. All the managers in La Liga are warned, they know what will happen if they say there's a foul."
Vilanova's side are currently top of La Liga courtesy of their two-from-two record so far.