2. Shane Day
If Joe Lombardi gets promoted and lands a head coaching gig with another team then there is no doubt that Shane Day is going to get a promotion next season as well. Day is different from the other two coaches on this list, though, because his promotion is just as likely to come with the LA Chargers as it is with any other team.
If Lombardi is hired by another team to be their head coach then Day is the logical selection to be promoted as the offensive coordinator. Day already works very closely with Justin Herbert and seems to have a great relationship with the franchise star. His transition to coordinator would, in theory, be a seamless one. That is the most important thing for Herbert.
However, he also could leave. There is the chance that if Lombardi is hired elsewhere that he would take Day with him to be his offensive coordinator. Granted, because Lombardi has such a great relationship with Brandon Staley, he would likely respect the Chargers and allow Day to be the coordinator there without interfering.
There is also the chance that Lombardi does not get hired as an offensive coordinator and Day has to get promoted elsewhere. There is a world in which not that many head coaching jobs open up and Lombardi simply misses out on the cut.
If the Chargers have a fantastic season offensively then there are going to be teams who need coordinators who will be looking to poach LA's staff. If that is the case, Day becomes the most obvious coach that could get hired by another team.
If Lombardi stays, Day's chances of leaving grow significantly. If Lombardi leaves then Day will likely stay in LA.