GREENSBORO, N.C. -- It didn't take long for the Atlantic Coast Conference to decide even was much better than odd.

Less than four months after the ACC added Miami and Virginia Tech to form an 11-team league, Boston College agreed Sunday to become the 12th member. The Eagles will likely begin play in the conference in 2006, ACC commissioner John Swofford said.

"An 11-team league can work, but does it work in the best way you would like to it to work from a number of different angles?" Swofford said. "We found the answer to that to be no."

No guarantee of a football playoff game and scheduling nightmares in a league with deep-rooted rivalries helped convince the ACC's chancellors and presidents to move swiftly to add a 12th team.

"It's almost like a suit, you put it on and wear it for a while and then you decide it needs some alterations," Clemson president James Barker said. "We began to envision ourselves in the summer as one sized league and we felt an adjustment would be wise to position us for the future."

Unlike in June when Duke and North Carolina balked at expanding, the vote Sunday was 9-0 in support of adding the Eagles, a charter member of the Big East.

"We had opposed expansion," North Carolina chancellor James Moeser said. "But once we became a conference of 11 the arguments for adding a 12th member became persuasive."

Boston College had until Nov. 1 to accept the ACC's offer, but agreed in less than four hours to jump leagues.

"We are extremely disappointed with Boston College's decision to leave," Big East commissioner Mike Tranghese said. "Our membership is very surprised that the ACC presidents continue to come back into our league for membership."

Big East by-laws require 27 months notice to leave that conference or face a reported $5 million exit fee. It's unclear if Boston College is willing to pay such a fine to join the ACC before 2006. Miami and Virginia Tech will begin ACC play next season.

"We are disappointed with the ACC's continued attack on the Big East Conference and in Boston College's decision to turn its back on its fellow members of the Big East," Pittsburgh AD Jeff Long said.

West Virginia deputy athletic director Mike Parsons was confident the Big East can regroup.

"The conference will be strong," he said. "It will come out of this thing. We'll have some rebuilding, but we'll come out of it."

The addition of Boston College will give the ACC the number of members required by the NCAA to stage a lucrative league championship football game.

Boston College and Syracuse were the Big East schools in the ACC's original expansion plans -- along with Miami -- but were voted down in favor of adding the Hurricanes and Hokies. Duke, North Carolina and N.C. State voted against adding Boston College at the time.

But other pro-expansion schools in the ACC kept pushing for another member.

Swofford said it wasn't awkward to approach Boston College again after the ACC had voted down the Eagles during the initial expansion plans.

"It became evident over the summer that was some continued interest on both parties part," Swofford said.

ACC bylaws require campus visits of each school being considered for prospective membership. That requirement was satisfied before ACC presidents initially rejected Boston College for membership in June.

"The ACC is a strong, stable conference," The Rev. William Leahy said. "The move to the ACC will generate greater revenues in the future."

Four Big East schools have filed suit against the University of Miami for leaving the Big East to join the ACC. A Connecticut judge dropped the ACC as a defendant in that lawsuit Friday.

Connecticut Attorney General Richard Blumenthal said Sunday that Boston College would be named as a defendant in the suit.

"Our claim is that Boston College is part of a continued conspiracy to weaken and destroy the Big East as a competitor for broadcast revenue and other rights," Blumenthal said.