Just going off of nailed on starters, what options do we have? All the wingers/attacking mids seem to be in contention for positions but no one safe, so knock them all off the list. Aside from defenders, we have Solanke at striker and Cook at CM that are nailed on (assuming no new purchases displace them). Both fullbacks, Smith and Kerkez, look to be strong favorites to start their positions when fit, so we can consider them. At CB, there's Zabarnyi and Mepham for the right side and Senesi and Kelly for the left, I'm not sure I see any of them being guaranteed starters at the moment just off of the friendlies and past form, though Iraola could have made up his mind and we just don't know it.
Assuming we get rid of the CBs, it's between Solanke, Cook, Smith, and Kerkez - the latter is young and just joined, so only the former 3. Don't think it'll be Solanke, never struck me that much as a vocal leader of the team - and Iraola would probably get charged with murder after
@Red_till_im_ded suffers a heart attack at the news. Smith and Cook both have bite to their game and a fair bit of seniority, could be either of them.
Options aside from Smith/Cook would be any CBs or GKs that manage to solidify their position as guaranteed starters.