[Adam]

A player's location is determined by his last (or current) point of contact with the floor.
Examples.
1. Player standing with one foot out and one foot in, lifts the foot that was out so only his inbounds foot is on the floor. This player is in bounds.
2. Player standing OOB, takes one step in bounds and jumps off the foot that was in bounds. This player is in bounds.
3. Your example, the player is in bounds, as his last contact with the floor was in bounds.

Basically, all that's required to be in bounds is to have something in and nothing out.

Hope this helps.