Prosinecki: Popular with Portsmouth fans (MarkThompson/Allsport)

The Croatia international announced his decision after a meeting with Milan Mandaric. Despite the Pompey chairman desperately wanting him to stay, Prosinecki announced his intention to leave Fratton Park.

The former Real Madrid and Barcelona midfielder has made a real impact for Portsmouth, winning the club's Player of the Year award and a place in the Division One PFA team of the year but despite his performances, Pompey finished a lowly 17th and several other clubs were interested in signing the Croatian playmaker.

Prosinecki said: 'I am sorry to leave Portsmouth, but I have an opportunity to go to Japan which I am excited about. My number one regret however is leaving the great supporters at Fratton Park.

'They will stay in my memory for a long time. I have enjoyed my relationship with the club and Milan.

'From the bottom of my heart I want to wish Pompey well and hope the team can give the loyal supporters what they deserve next season with a lot of joy on the field,'' he told the club's official website.

Mandaric added: 'I tried very hard to convince Robert and it is a tribute to the way the club is going that he had to think about it long and hard.

'At the start of the season we made a deal, as two friends, that he would come here to help us out, but if there was a substantial higher offer made to him then I would not stand in his way.

'He is one of the few players I have met who is not greedy, but this was an offer which he could not refuse and will enable him to take care of his young family.

'We will miss him on and off the field and I am sure everybody will join me in thanking him for all the entertainment he has provided this season.

'It has been a great honour to see Robert in the blue shirt of Pompey even if it was just the one season.

'Though I am disappointed he will leave behind him a lot of great memories and warmth.

'He is coming to the twilight of his career and in the end this opportunity was too tempting for him to turn down.'