Rodgers told BBC Sport "It was difficult because of the pitch to get our fluency going in how we play
"It obviously hasn't been cut, which doesn't surprise me.
"The pitch was very difficult" continued the Swans boss. "It didn't look like that for the Under-21 match.
"We have seen it over the years – you get a football team coming to a ground and it's your prerogative being the home team.
"But I'm surprised at this level that you walk out on to the pitch and it isn't even cut.
"It was not the performance level we've been at for most of the season.
"It wasn't that Preston had to do anything fantastic to open us up, there were too many gaps.
"Iain Hume did very well today," added Rodgers. "He was excellent, his energy was good, he was dynamic strong and aggressive in his running, and a goal from his perspective.
"But for us, how we've defended this year and how we've been, that was very disappointing.
"It's a concern only because we would want to do better," he added. "But thankfully I've got a group of players who respond fantastically well to the downs of football.
"They're obviously disappointed in there because they know that we haven't really done ourselves justice today.
"If we have ambitions to go up automatically, [Norwich] is a game we have to get something from and we will look to get a win."