I'd just play King at RW where he has been playing well and stick Gemmell at C. He'll regain his form. Also, move Manera back to LW, IMO.
Manera's always been at LW. Gemmell is in pitiful shooting form and all his oher stats are shit, so he's useless. Was an experiment with King but Cambridge will probably have to come in.
It's your choice. But Gemmell was solid in the Season, and it shows he can play well. He;s not going to come out of a form slump without playing.