Not really a bad thing that.
It is when they have no other centerbacks. I could see Luiz coming back for the finak, Bobby hasn't ruled him out for the season yet.
Obviously the result didn't go our way, but that was a remarkable match. I'll get over Chelsea winning (unless they win in the final and we miss out) for the sake of football. Matches like that are one of the main reasons we all watch football.
They can with the overage players, iirc.
There's apparently a clause in Beckham's contract that allows him to play in the Olympics if called up, not sure why it would exist if they couldn't prevent him from going.