Hazard was replaced by Andre Schurrle inside the opening 18 minutes of the match at Stamford Bridge last night.
The German international gave Chelsea a first-half lead, with substitute Demba Ba netting the all important second goal in the 87th minute to send Jose Mourinho's side through to the semi-finals of Europe's elite competition on away goals.
Hazard's injury was the only downside of a superb night for Chelsea, with Mourinho revealing the Belgium international will be missing for the next couple of weeks.
"It is a calf problem, but I have no idea the dimension of his injury," said Mourinho.
"Even when they are not serious, you cannot play for a couple of weeks."
The Belgium star will definitely miss the upcoming clashes with Swansea City and Sunderland, but could be absent for the first-leg of Chelsea's Champions League semi-final.
If Hazard is only ruled out for the minimum of two weeks, he could make his return in what could be a season defining match against Liverpool at Anfield on April 27.