Croatia v Slovenia Croatia coach Otto Baric has problems in defence and midfield, with Robert Kovac of Bayern Munich suspended and Josip Simunic from Hertha Berlin out with an ankle injury picked up in training. Both should be available for the second leg.
But he will also be without midfielder Milan Rapaic who has not yet recovered fitness after injury.
Baric is still considering whether to field 19-year-old Dinamo Zagreb midfielder Niko Kranjcar, who could give additional edge to in-form strikers Dado Prso of Monaco and Ivica Olic from CSKA Moscow.
Slovenia received a boost when Zlatko Zahovic, now fully recovered from the toe injury that kept him out for six weeks, and Ermin Siljak, top scorer in the qualifying campaign, joined up with the squad.
Defender Aleksander Knavs, nursing a light injury, should be in the starting line-up but first-choice goal keeper Marko Simeunovic has a shoulder injury and is likely to be replaced by Mladen Dabanovic.
CROATIA (probable): Stipe Pletikosa; Dario Simic, Igor Tudor, Boris Zivkovic, Stjepan Tomas; Mato Neretljak (or Marko Babic), Jerko Leko, Niko Kovac, Ivica Mornar; Dado Prso, Ivica Olic.
SLOVENIA (probable): Marko Simeunovic or Mladen Dabanovic; Fabijan Cipot, Spasoje Bulajic, Aleksander Knavs; Goran Sukalo, Nastja Ceh, Miran Pavlin, Amir Karic, Milenko Acimovic; Zlatko Zahovic, Ermin Siljak.
Referee: Markus Merk (Ger).