Lampard, and perhaps Haji himself believe his best/natural position is centre forward. Despite a few memorable games down the middle (including a couple of hat tricks) I still feel he's more threatening and impressive playing off the left side, where he seems able to receive and carry the ball much better. Even in yesterday's match against Wednesday, his best contribution was that run and clipped cross for BTA.
In the absence of Sakamoto, I'd be tempted to play EMC on the right (absolutely no reason why not IMO despite some mad takes on here about his early performances for us). Simms at CF and Haji on the left. We hardly ever get to see Simms and Wright play together, which is a pity (think Wolves!!).
And thinking about next year, if Haji is still here I'd see him as basically providing options across the front line? At his best he's awesome but it's quite a rare sight, and I doubt he'd be an automatic starter as a lone striker in the Prem.