Almost four years after the N.F.L. agreed to pay hundreds of millions of dollars to ex-players who said the league had concealed the dangers of concussions from them, the first payouts — some worth as much as $5 million — have been approved.
But the registration process will end on Monday, closing the window during which players can potentially receive cash awards. More than 18,400 out of the roughly 21,000 retired players have registered, a necessary step before they can undergo medical tests and apply for benefits. About $100 million in awards has been approved so far.