No way is he playing as a striker. He's in a midfield two with Pirlo - ostensibly Frank on the right, Pirlo on the left; Pirlo plays from deep and Frank has the remit to be involved in the attacking play, linking with the front three. If he was playing up front, you'd only see him trying to get on the end of moves, as it happens he gets on the end of lots of things because he's Frank Lampard and that late arrival and finishing has been a hallmark of his play.
But, he's playing midfield, that's for sure, just in an attacking role and doesn't seem to have the legs to get back to defend a lot.