Cassano was reacting to Saturday's 0-0 draw with Genoa.
He said on Bobo TV: “Roma are playing badly and I don't want to use excuses linked to incidents or anything else. Against Genoa you have to win because you're stronger. Of those in the top half of the table I think the Giallorossi are the biggest disappointment.
“After the first few months with a very good football proposal, the candle has gone out. And I don't know if it's down to the 6-1 win over Bodo or the players or something else. For sure Mourinho needs to be given more time, but today the team is suffering, struggling and has no tactical idea.
"I don't think Mourinho has yet managed to provide the stability the team needs."