Bundesliga strugglers Borussia Dortmund have agreed to sign Slovenia international Kevin Kampl in January.
Cardiff have agreed to sell Norwegian midfielder Mats Daehli to Freiburg in January.
The Isolani, who remain the only side without a win in Serie A this season, have turned to their former midfielder just hours after publicly denying speculation that Ficcadenti's job was at risk.
The 44-year-old has now been sacked by the Sardinian club twice within 11 months, having been dismissed last November only to return to the club in March.
A statement on cagliaricalcio.net read: "We can confirm the end of the working relationship between Massimo Ficcadenti and the club.
"He deserves our thanks for what he did for Cagliari Calcio.
"Preparation has now begun for our game at Torino on Sunday, and today's training session was directed by our new coach Ivo Pulga and his staff.
"Diego Lopez will act as his deputy and he will also be assisted by goalkeeping coach Nico Facciolo and Luigi Corellas.
"Pulga will be presented to the press tomorrow afternoon."Earlier tonight, the Rossoblu moved to reject media reports in Italy that Lopez had been appointed as Ficcadenti's sole replacement at the Stadio Is Arenas.
A statement published on cagliaricalcio.net read: "There have been various newspaper articles that have placed our youth coach Diego Lopez in charge of the first team, even though he does not have the necessary qualifications.
"The club would like to make clear that when any changes to the technical staff are made, they will be announced through our channels.
"Any decision will be made in full respect of the rules and regulations of the governing bodies.
"When and if any decision is made concerning a new first-team coach, it will be someone licensed to both carry out the specific technical functions of the role and to lead a team."
Pulga, who was most recently working for Serie B club Modena's youth set-up, formed part of the team that won promotion from Serie C1 to the top flight under the stewardship of Claudio Ranieri.
Despite not having the necessary qualifications to coach a Serie A club, former Uruguay international Lopez can work in partnership with Pulga as the duo plot Cagliari's swift rise up the league table.