1,545 players began their Main Event quest today. 1,606 are registered to play tomorrow (Day 1C) and with the exception of emergency cases, everyone else from this point forward who decides to pony up the $10K for a shot at immortality will be required to start play on the newly-added Day 1D.
So, we're looking at around 6,000 players total for this year's Main Event. That is of course significantly fewer players than last year, but still a staggering $60 million prize pool.