Villarreal suffered in the first leg due to a number of first-team injuries, but now it looks like the Dutch side will suffer this time.
Jan Kromkamp (ankle), Tim de Cler (mild concussion), Joris Mathijsen (inflamed tendon) and Barry Opdam (muscle) are all major doubts for this game.
Los Submarines have an injury worry over Javi Venta, but Juan Manuel Peña (ankle) and Quique Álvarez (knee) are definitely ruled out.
To advance to the semi-finals, Villarreal need to win by two clear goals or at least grab a win whilst scoring more away goals than AZ netted in El Madrigal (2).
Uefa Cup Track Record: P6 W3 D0 L1 GF6 GA3
Rd 32| Aachen 1-2 Alkmaar (0-0, 1-2)
Rd 16| Shakhtar 2-5 Alkmaar (1-3, 1-2)
Uefa Cup Track Record: P4 W2 W2 L0 GF8 GA2
Rd 32| Dynamo Kyiv 0-2 Villarreal (0-0, 0-2)
Rd 16| Steaua 0-2 Villarreal (0-0, 0-2)
Uefa Cup| QF| 2nd leg| Thursday| 14 April 2005| 20:30 CET| Almaarder Hout.
Viasat Sport 2
AZ Alkmaar 1-3 Villarreal CF