Robinho completed his loan move to former club Santos last night.
And in his column for The Times, Cascarino wrote: "Goodbye and good riddance to the worst signing in Premier League history.
"Not the worst player, of course: Robinho is hugely talented. And with 14 goals in the league last term, you couldn't say he disgraced himself in his debut season in English football. But if there was a statistic that linked cost with commitment, wages with workrate, he would be right at the bottom of the value-for-money table.
"Other expensive flops failed in England because they were not good enough, not managed properly or failed to adapt to the life or the style of play.
"Juan Sebastián Verón? Just not suited to the Premier League. Andriy Shevchenko? A player in a sharp physical decline. That's forgivable. He did his best.
"Robinho failed because he was uninterested. As a former player who tried to work extra hard to make up for my technical limitations, seeing someone so gifted yet so lazy disgusts me."