3rd strike checked swing, uncaught by catcher

[fredhjr]

USA As it was told to me: No outs, no base runners. Two balls, two strikes on batter. Batter checks her swing, ball goes past catcher to the back stop, batter runs to first base. No call by the PU, who does not ask FU for assistance on the swing. Defensive coach asks if the batter swung for a third strike. This does not appear to be a play that can be appealed, according to my understanding of appeal plays. However, I am seeking opinions.