The Danish international was unwell, but the Reds boss praised Mamadou Sakho for his performance in place of Agger.
Rodgers told the club's official website: "Daniel felt sick this morning when we arrived at the training ground. But a more than capable replacement came in, who I thought was excellent.
"I thought Sakho looked strong and aggressive and he looked like he really wanted to take his opportunity. He did that. I thought he and Martin Skrtel were both excellent."
The victory moved the Reds to second in the Premier League.