Adelaide United are facing a mass exodus as players begin to pursue careers elsewhere. It is understood that five players from the current 17-man Reds squad have been given permission by the club to begin transfer negotiations.

Defender Scott Jamieson, goalkeeper Mark Birighitti, midfielder Fabien Barbiero, and defensive duo Daniel Mullen and Robert Cornthwaite have all been given permission to commence transfer talks with other clubs.

Jamieson trialled with Dutch club Groningen FC prior to Adelaide's pre-season training kick-off but said it was more for experience and a move was a fair way off.

The move regarding young goalkeeper Birghitti has been in the news recently with the Reds keen to keep him in Adelaide, so much so they priced him at $1 million.

Barbiero and Mullen are both being lured towards Europe, with the latter trialing with NEC Nijmegen in March and Cornthwaite has had offers from clubs in South Korea.