I am absolutely sure that Berba will stay at least one more season. If Jol gets another good player (or maybe 2) that are working good together with Berbs, he will be happy enough to stay a little bit longer.
If Berba makes even more progress it will be hard to keep him, of course. I think every player wants to play for a really big club once in his lifetime, though most of them don't become very happy at a big club and spent much time on the bench, if they are not a ronaldo, ronaldinho, zidane, etc.
However, I'm sure he has enough brains to think about such a decision very carefully and that he is not so keen on money to ignore everything else.
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