The Belgium midfielder has been linked with Manchester City in recent days.
However, Chelsea have first option on Hazard for a set fee of €15 million and BILD says the clause will expire in January.
For his part, Hazard insists he's happy at Gladbach, "I signed a contract here because I want to play here.
"I'm not wasting a single thought on Chelsea, I am totally focused on my job here. Borussia helps with my goals."