Cagliari president Massimo Cellino has branded their campaign a "failure".
The Sardinians secured their Serie A safety around two months before the end of the season, but took their foot off the accelerator.
"It is true that at the start of the season our objective was just to stay in the top flight, but once we reached 39 points we could hope for something more," said the patron.
"There were 15 games to go and we could easily have qualified for Europe, but instead we ground to a halt.
"I consider this season to be a failure."