Central Coast captain Alex Wilkinson has edged closer to a move to South Korea's K-League after his A-League side allowed him to meet a club chasing his signature.Amid speculation the long-serving central defender could leave the Mariners after seven seasons, the club confirmed on Wednesday Wilkinson would fly to Korea to trial with reigning K-League champions Jeonbuk Motors.The Mariners released a statement saying no transfer deal had been reached but confirmed Jeonbuk were interested in signing the 27-year-old, who holds the second-most A-League appearances with 172."The Mariners are committed to allowing the popular, long-serving defender the opportunity to discuss personal terms and decide whether a move to the K-League may be of interest to him and his family," the statement said.It means Wilkinson could follow former Mariners teammates Matt Simon and Rostyn Griffiths in securing lucrative moves within Asia.His departure would come as a significant blow to Central Coast, who claimed last year's Premiers' Plate.The Mariners will definitely be without long-serving utility Brad Porter next season after he called time on his playing career on Wednesday due to a serious knee injury.The 25-year-old defender, who made his A-League debut in 2006/07, spent more than six years with the Mariners, making in excess of 90 competitive appearances.Porter suffered the injury in the 2010/11 season and has struggled to make a full recovery since."It's been a tough decision to make to have to retire from the game but, at the end of the day, I did the injury nearly two years ago now and, in that time, it's been extremely frustrating trying to come back and having setbacks," Porter said."... I'm very proud of what I've achieved at this club."To have been here from basically day one and to have seen the growth of the club both on the pitch, and building the supporter base and the community support, has been unbelievable."Porter said he would pursue a career as a coach and plans to spend time around Graham Arnold's squad to gain experience.Arnold described Porter's retirement as a tragedy."We wish Brad, as a guy who is a Mariner through and through, the best for the future," Arnold said.