The Reds make the trip across the border to Tannadice on Thursday for the first leg of their qualifier.
"Hearts will be a very, very difficult game for us," Rodgers told reporters. "I've still taken a squad here that is a strong group.
"It will be a difficult game. Tynecastle is a wonderful, tight little ground and supporters will be behind their team and there are some good players."
The Merseysiders beat Belarusians FC Gomel 4-0 on aggregate in the last round.