Chelsea are interested in Feyenoord defender Stefan de Vrij.
The young centre-half is inside the final two years of his current deal and stalling on penning new terms.
"I cannot just sign. I am open to a contract extension, but before I sign we must first negotiate," he said.
Voetbal International says Chelsea are monitoring developments closely. De Vrij has also been a long-term target for Arsenal chief scout Steve Rowley.