Uefa has confirmed that there will be no provision in the Champions League quarter-final draw to keep teams from the same country apart.
That means Manchester United could be drawn on Friday against Liverpool or Arsenal if the Gunners qualify from Group D.
Spain's Real Madrid and Barcelona could end up facing Deportivo la Coruna depending on the results of the last set of group games tonight.
"For the quarter-finals, each of the four runners-up during the second group stage will be drawn against a group winner (but will not be drawn against the winner of the same group)," Uefa confirmed in a statement.
"In this draw, teams from the from the same national association can meet each other.
"There was some confusion because, at the earlier stages of the competition, we kept teams from the same country apart," said a Uefa spokesman. "But there will be no such seeding for the quarter-final draw."
Manchester United finished top of Group A and will be drawn against either Liverpool from Group B, Arsenal or Deportivo la Coruna from Group D or Panathinaikos or Porto from Group C.
Real Madrid and Barcelona avoid each other after they finished top of Groups C and B. Either could face Deportivo la Coruna if the Spanish club finishes second in Group D.