Richards looks like the natural reference point in a back three.
That matters because the alternatives each solve a different problem. Tim Ream brings experience and calm, but at 38 he is no longer the automatic answer he once was. Auston Trusty and Mark McKenzie have reportedly strengthened their cases with recent US starts, while Miles Robinson offers recovery pace but is still trying to fully re-establish himself after the injury setback that disrupted his previous World Cup push.
The wider defensive picture looks clearer. Antonee Robinson and Sergiño Dest appear the leading wing-back options, which gives the US natural width on both sides. In goal, the update says Matt Freese has handled much of the work since Pochettino took charge, with Matt Turner still firmly in the frame.
That leaves the main tension in central defence: experience versus legs, familiarity versus form. If Richards is unavailable or limited, the US may have to become more conservative without the ball.
Midfield and attack bring fewer certainties than star names suggest.
The next storyline is obvious: the fitness updates. If Richards returns quickly, Pochettino can build from a stable defensive spine. If not, the US coach may head into the tournament still searching for his best back line.