Borussia Dortmund coach Edin Terzic admits it's been difficult to prepare for their Champions League round 16 clash with Chelsea.
The Bundesliga side are in superb form, winning all six of their matches this year and currently sit third in the league.
However, head coach Terzic says it will be difficult to know what to expect from their English opponents with Chelsea spending lavishly on the likes of British record signing Fernandez in January while still being without N'Golo Kante.
"It is not easy to analyse [Chelsea]," Terzic said.
"After the Champions League draw we watched their games but then in the transfer window there was so much movement from them.
"They sold key players, brought in other key players. Then we saw the official Champions League list but then there was the transfer of Joao Felix, for example," Terzic added.
"So you don't know how they will play. In defence they played with four but before also with three in the back. We will prepare for everything."
