Sand - 3:18 pm on Jul 2, 2013 (gmt 0)
I think it's a definite possibility.
A friend of mine had a site that was decimated by the first Penguin. Prior to that, he had been at the top of the rankings for hundreds of terms for many years.
Analysis showed that he had very few backlinks pointing to his site, and the ones that he did have were editorially given from trustworthy sources. Nothing fit the pattern of what we know about Penguin, so it was a bit of a mystery.
The only thing we could find is that he was fairly spammy with his internal links. That said, cleaning them up never resulted in a recovery.