Pitcher is on the rubber with a runner on 1st. Runner attempts a steal and the pitcher, while remaining on rubber, does nothing. Runner reaches 2nd base and is standing while the pitcher never moved. Time-out has not been called. The pitcher delivers the ball and it is fouled off. Does the runner have to go back to 1st base because this is a foul ball on an attempted stolen base?

1 minute ago, PP1 said:

Pitcher is on the rubber with a runner on 1st. Runner attempts a steal and the pitcher, while remaining on rubber, does nothing. Runner reaches 2nd base and is standing while the pitcher never moved. Time-out has not been called. The pitcher delivers the ball and it is fouled off. Does the runner have to go back to 1st base because this is a foul ball on an attempted stolen base?

Nope. 

I agree. Runner was on 2nd base before the pitch was delvered. That is the base he returns to on the foul ball.

Does the beginning of the pitch start with the foot on the rubber or the pitcher moving his leg? Is there a difference between this and just getting an early jump? Time was not called and the pitcher never left the rubber. 

2 hours ago, PP1 said:

Does the beginning of the pitch start with the foot on the rubber or the pitcher moving his leg? Is there a difference between this and just getting an early jump? Time was not called and the pitcher never left the rubber. 

It definitely does not start with just the foot on the rubber, otherwise a batter would never be able to call timeout once that happened.  I don't have a rule book in front of me to give you a definitive answer, but I'd say it's after he begins his movement towards home once he's come to the set position.  In the original scenario, the runner had already advanced to second base before this happened...therefore that's the base he would have to return to after any subsequent foul ball.  That'd be my guess.