Is this offside in soccer?

[Bradthelad]

A defender boots the ball down field to an offside player who is standing in the attacking half of the field near halfway. The attacker runs into the defensive half of the field, but without touching ball he runs back into the attacking half and touches the ball.

Is this player offside because he was in a offside position when the ball is kicked?
Is he onside because he ran back into the defensive half of the field?