Barca made an attempt for Rudiger in the final days of the summer market and are still keen, reports Mundo Deportivo.
Barca will seek to set up a loan arrangement for Rudiger, who would arrive as cover for knee injury victim Gerard Pique. Pique isn't expected to be seen again until March - at the earliest.
Rudiger has recently forced his way back into Chelsea's first team and has declared a wish to remain in London.
But a guarantee of regular football may convince the German as he seeks to stay in Jogi Low's plans for next year's Euros.