Today's Daily Telegraph says the 25-year-old failed a test early in the season after the round two match against Melbourne Heart, with traces of a recreational drug found.

Hearfield is said to have faced a tribunal two weeks ago and is awaiting his penalty, which could span from anywhere between one to five years.

Hearfield is believed to have first denied taking the drug, before changing his story and admitting it soon after.

Today the Mariners said the former Newcastle Jet and Welington Phoenix utility midfielder then approsched the club in early Ferbuary and asked to be released from his contract.

"The club and Troy then mutually agreed to terminate his contract at that time," said a statement from the club today.

"No further comment regarding this matter will be made by Central Coast Mariners until such time as the process is complete."

Hearfield made 115 A-League appearances across his three clubs, winning a title with the Jets back in 2008, but usually only featuring off the bench for the Mariners since joining them in 2011.

Hearfield is the second A-League player to fail a drugs test since the competition's inception eight years ago.

Former Socceroos winger Stan Lazaridis also tested positive while playing for Perth Glory, for taking a prescription alopecia medication.

Lazaridis was handed a one-year ban although the drug found in his system has since been withdrawn from the banned list.

The Mariners, who finished the regular season in second position, have the opening weekend of the finals series off before hosting the highest-ranked winner from week one on Sunday week.