The club’s coaching staff made the tough call on the trio which will see them all move on after the current Hyundai A-League campaign.

Adelaide United Coach Aurelio Vidmar admits the decision to release the trio was an extremely hard one, but is adamant that they are all still a valuable part of the club’s championship ambitions this season.

“It’s a very difficult decision for the coaching staff because all three have contributed positively during their time here but unfortunately with the direction the club is moving into, they are not part of our plans,” Vidmar said.

“However, all three will still play a very important part in our finals campaign as we try to win the championship.”

Vidmar lauded the trio’s contribution to the club both on and off the field and said they each had a significant impact in the club’s success.

“We truly appreciate everything each of them has done for the club during their time here and it is never easy releasing players but it’s a part of the game,” Vidmar said.

“Once the season ends, we wish them all the best in whatever the future holds for them.”

Costanzo has been a favourite amongst Reds fans since he joined United prior to the inaugural Hyundai A-League season, the former Qantas Socceroo always providing a physical presence and experienced head whether he lined up in defence or midfield.

Signed by United from Miami FC back in January 2007 after the American team’s tour of Adelaide, Diego has made 28 appearances for The Reds in the Hyundai A-League, the creative playmaker seeming to save his best for the big games, particularly the 2008 AFC Champions League where he scored three times in the Group Stage and a crucial goal in the first leg of the Semi Final against Bunyodkor.

Salley, 26, has spent two seasons in Adelaide and has provided a strong, uncompromising edge to United’s midfield stocks.

The trio’s departure adds to the list of names who will not be at the club next season, which include Paul Agostino and Michael Valkanis, who have both announced their retirements, and defender Sasa Ognenovski, who is heading to Korea to join K-League club Seongnam Ilhwa.

Isyan Erdogan’s contract will also not been renewed, the Melbourne born defender spending the 2008/09 season on the club’s long term injury list.