In the current Barca squad he is more likely to get a place as winger, on the left side, because there's less competition there. Therefore he can show what he can do better in that position. Imo though I think that Bojan would be perfect playing in the hole, for example in a 4-4-1-1 formation, or others that use a forward/playmaker. Bojan has shown a great eye for passes but not the through balls that a midfielder like Xavi could make. Instead he can play a good ball to a CF like Ibra, who would hold the ball and let Bojan dart past him, who can then score.
That's a very unlikely formation for Barca though and so I'd see him at his best as a central striker for us.