The Reds began the game brightly enough, with opportunities to break the deadlock created but spurned.
Rodgers' side were made to pay for their inability to turn possession into goals when Christian Benteke fired the visitors in front.
A second from Andreas Weimann and another from Benteke put Liverpool out of sight, ensuring a late reply from Steven Gerrard counted for little, and Rodgers was forced to admit at the final whistle that his team had allowed their standards to dip following a recent upturn in fortune.
"I think that will be the growth and the process with the group - it's never linear, it's never straight up," he told Sky Sports on the up and down nature of Liverpool's season.
"It's a disappointing result for us and performance, which I didn't really know where that was coming from because it's out of context with the way we have been performing.
"We had the opportunities to be two or three goals up early on in the game, but were careless with our final ball and didn't end up taking the chances. It's always the danger if you don't take the opportunities, you can get punished.
"Aston Villa came and defended well and when they got the goals, they weren't having to come out and chase the game. It was important for us to try and get the first goal today, to try and get Aston Villa out, but it wasn't to be.
"We didn't quite have the intensity and the quality to our game today. We just need to take that as a bad day at the office and move on."
Liverpool have struggled to generate positive results at Anfield in 2012, but Rodgers claims to have taken plenty of positives from the performances he has overseen.
He added: "To be fair, apart from the Arsenal game, we have been good here at home and we have created chances.
"I just felt today that we weren't quite sharp enough with our final pass. I thought today was a lot different to many of our performances this season at home.
"Today we weren't as intense with our pressure without the ball and unfortunately we didn't take the chance to win a home game."
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