Juventus, who won three Italian league titles in a row under Conte, have also signed 18-year-old Spanish defender Carlos Blanco Moreno, who arrived on a free transfer on the expiry of his contract with Barcelona.
In a furious attempt to make good on his long-lost promise, Van der Gun has hinted at a free transfer to Feyenoord at the end of the year.
Ballack was once one of their influential number, in among a cabal of players who could make or break a coach, before departing on a free transfer as part of a blood-letting of high-earning personnel in the summer of 2010.
McPhail, who moved to Cardiff in 2006 from Barnsley on a free transfer, is out of contract in the summer but has settled his young family in the Welsh capital and has been taken to the hearts of the Bluebirds fans.
The West Ham United co-owner concedes that allowing the Senegal striker, who has scored 16 goals in 21 Premier League appearances this season, to join Newcastle on a free transfer last summer was one of the biggest mistakes of his life.
And they could face the prospect of losing the player on a free transfer at the end of the season if they don't take action.
The 30-year-old, who once cost a reported £22million, will join on a free transfer until the end of the season, with the option of extending his deal by a further year.
The Serbian centre-back, 32, announced in March that he is to join Serie A club Inter on a free transfer upon the expiry of his contract at the end of this season.
"However, given the fact that we are now seven weeks away from the end of the season and Michael could leave on a free transfer at the end of his contract, this deal represents good business for the club.
I never did get my place back and was given a free transfer at the end of the season.
