Kevin Mahon's Derry City side face Shelbourne on Friday

Derry City have signed Northern Ireland youth international Mark McCrystal from Wolverhampton Wanderers.

The 18 year old central defender opted for a return to his home town after being told that he had no future at Molineux because of cutbacks at the club.

McCrystal had been at loan for Bradford City in recent weeks but he has decided to return home to finish his studies.

Derry, meanwhile, have turned down an offer from Longford Town for midfielder Ciaran Martyn.

The former UCD player was unhappy at being substituted in last Thursday's 3-2 defeat by Longford and walked straight to the dressing-room after he had been taken off.

At that point, there was speculation Martyn had played his final game for Derry but manager Kevin Mahon has insisted that he remains on the club's staff.

Shelbourne, who face Derry in the Eircom League at Tolka Park on Friday, have also made a tentative enquiry about Martyn's availability.