Teams that finished first and second in the league phase will face the winners of the knockout phase play-off ties involving the 15th, 16th, 17th and 18th-placed teams in the round of 16.
Lazio, Athletic Bilbao, Manchester United, Tottenham, Eintracht Frankfurt, Lyon, Olympiacos and Rangers qualified automatically for the next phase and will be joined by the eight winners of the two-legged play-off ties with those second leg ties taking place on Thursday.
Teams that finish third (United) and fourth (Tottenham) will be drawn against the winners of the knockout phase play-off ties involving the 13th, 14th, 19th and 20th-placed teams.
United and Tottenham are both enduring miserable Premier League campaigns with winning this competition their only hope of qualifying for the Champions League next term.
Manchester United, Tottenham and Rangers will learn their Europa League fate this week in the round of 16 draw.
