Wow, is Mike on vacation?

According to ASA rules; Base stealing is legal in Adult Men's Slow Pitch (does not apply to Men's Master and Senior Play). A runner may leave the base when the ball reaches the front edge of home plate (provided the ball has not touched the ground prior to reaching the front edge of home plate).

Which means that the ball remains live after it reaches the front edge of home plate and the batter swings and misses. Consequently, the runner may steal, provided he does according to ASA rules.