The umpires have the authority to stop play at any time if it is determined that a player needs immediate medical attention. Umpires are usually instructed to only do this if the situation is "life threatening", but it is left up to the judgement of the umpires. It is an immediate dead ball and any runners are awarded the base they would have reached in the umpires judgement.
In this particular case, the umpire thought that the pitcher was hurt badly enough to require attention. That was his judgement. It's just unfortunate that the ball rebounded off the pitcher directly to the SS who was able to throw to first. Once the ball is dead, no further plays are possible and the batter runner has to be put somewhere.
In this particular case, the umpire thought that the pitcher was hurt badly enough to require attention. That was his judgement. It's just unfortunate that the ball rebounded off the pitcher directly to the SS who was able to throw to first. Once the ball is dead, no further plays are possible and the batter runner has to be put somewhere.
