With Carles Puyol suspended and Rafael Marquez injured, Barcelona look horribly exposed in central defence, especially with the powerful presence of Didier Drogba poised to overpower whoever is drafted in.
Amid the jubilation of Barcelona's 6-2 thrashing of Real Mad rid on Saturday, Chelsea's spies will have reported back that Real's two goals were via the heads of Gonzalo Higuain and Sergio Ramos courtesy of slack marking in the middle.
Ballack and Terry will have loved every word of Barcelona's complaints and no doubt plan to deliver a similarly uncompromising welcome on Wednesday.
Hiddink, aware of his side's set-piece and aerial threat but also concerned by Barcelona's dangerous attack and ability to snatch an away goal, is likely to start with the same steady approach with Drogba ploughing a lone furrow up front.
Nicolas Anelka, who scored his 22nd of the season on Saturday, will be desperate to start but is more likely to return to the bench, from where can be introduced to add more variety to Chelsea's attack if plan A fails to come off.
"I like to have a flexible team," Hiddink said after seeing his two strikers operate successfully together again. "I don't want them surprised with two strikers playing together.
Barcelona: 1-Victor Valdes; 20-Daniel Alves, 3-Gerard Pique, 2-Martin Caceres, 22-Eric Abidal; 6-Xavi, 24-Yaya Toure, 8-Andres Iniesta; 10-Lionel Messi, 9-Samuel Eto'o, 14-Thierry Henry.
