Graham Arnold vows to return to Central Coast Mariners Graham Arnold: "I was very sad to leave the Mariners and I apologise to the supporters and everyone else for the way I left." Outgoing Central Coast Mariners coach Graham Arnold has apologised to the club's fans for walking out at such short notice - and has promised to return one day. While a move to an Asian club had been mooted for some time, and the Mariners had made basic contingencies for his departure, the speed of his appointment at Vegalta Sendai last week was a shock to many. Arnold returned to the Central Coast on Thursday to formally farewell the players and said he didn't want any bad feelings surrounding his departure for the J-League. "I was very sad to leave the Mariners and I apologise to the supporters and everyone else for the way I left," he said. It happened so quickly. On Sunday night, I got the phone call to say a Japanese club was interested. On Monday, the deal was done - and I flew out on Wednesday. I'll enormously cherish this club and I'll be at all their home games before I leave. However, Arnold said he would love to return to the club that helped salvage his reputation after a torrid ending to his time in various national coaching roles. "I will be back one day," he said. I love this place and I bought a house up here. I have the highest regard and respect for the football club, especially to Peter Turnbull [chairman] and Mike Charlesworth [owner], who've let me further my career. Arnold, 50, said he couldn't turn down the opportunity to join the "English Premier League of Asia." "It's going to be an enormous challenge, but one that I'm looking forward to," he said. Life on the [Central] Coast is great and I had a three-year contract and could have been very happy here but I've always been a person who needs a challenge. New coach Phil Moss, formerly Arnold's assistant, has the full confidence of his old boss. "Hopefully, he's learnt a lot from me over the last three years," Arnold said. He's got a wonderful stable group of senior players that are very good for him to lean on and he's got some quality youngsters. Thoughts have already turned to who Arnold might bring to Sendai, a club that has finished second and ninth in the past two J-League campaigns. Former Mariner Tom Rogic has been mooted as a loan option, while Western Sydney's Aaron Mooy may be another target. "I've had a conversation with Tommy, and if it wasn't about coming on loan to Sendai, it was more about being his ex-coach and what he needs as a footballer," he said. At the moment, he's a Celtic player, but I'd always find a spot in my team for Tommy Rogic. Hopefully can get game time here. Meanwhile, the Mariners have announced former defender Wayne O'Sullivan as Moss' assistant. O'Sullivan, who was part of the club's inaugural A-League squad, said he was amazed by the organisation's progress in the past eight years. "It's been six-and-a-half years since I've been here, so I am very excited to be back," he said. My first impression is that the culture here has gone way beyond what we were first part of. It's gone to a professional level that is way beyond where we were, and this facility [the club's centre of excellence] is incredible. Elsewhere, the FFA has defended itself from accusations that last week's match between Perth Glory and Adelaide United should have been postponed. Head of the A-League Damien de Bohun said the wet bulb globe test (WBGT) - the standard climate test for determining player safety - was 0.9 degrees short of the level considered dangerous. "The WBGT in Perth just prior to kick-off on Saturday was 27.1C, so the conditions were not considered unacceptable," he said. Everyone should rest assured that player safety was given primary consideration.