A Salmon and Haywood combination at lock is non threatening to the opposition, injecting Hutchinson there won't fix that. Curran is preferably on the field when King is not, I can't see Curran starting at 13. I said before the game that I would prefer one more big forward on the bench and use Curran/Hayes/Morrin/ Hayward at lock, then Hayes would likely start there which isn't ideal but I would prefer him to Salmon. The only options in NSW Cup are Fifita, Patolo, Hopoi or Todd. Fifita has been average in the few games he's played, Patolo struggles to last 10 minutes at NRL level without getting Injured and Todd has played about 2 games in the last 10 weeks, Hopoi I still needs to develop. It is a massive weakness the lack of reasonable big middle forwards though Mann was not big.
It's a big problem. Defensively Mann hits like a truck in the middle. Last time Mann was out for a while we got smashed by the Roosters and won a tight one against Sharks. Manly went through the front door with even that fat slob Nathan Brown making meters. Unfortunately Hayward, Hutchinson and Salmon just don't have the same skills with line speed and hitting ability.
In attack, Mann engages the defensive line and is a threat. This means he will probably get smashed most of the time, but THIS makes room for others such as Burton, Tracey, Kikau and Sexton. Very selfless and courageous thing to do. Anyone with any self preservation will not do this, and anyone who doesn't probably doesn't have it between the ears and skills to pass the ball well enough. The only other person that can do this well is Yeo.
For now, I think the loose forward role needs to go back to a defensively minded one and not as an attacking first receiver. The only person that can do this is Preston. He must play 80 and during the game, he can move from the edge into the middle and Hayes then can run on his edge. We lose his attacking prowess, but that means that larger packs won't steam roll us down the middle. If our objective is to get into a grind, then we must control the ruck. We have no chance to win if we don't control the ruck.
Like you mentioned, Curran at the moment is on for King. Curran could play at loose forward if we bring a prop onto the bench like Underhill, Farmer, DSF or Todd. They don't have to set the world on fire, just tackle hard and run hard.