what happens if a pitcher hits a baserunner while trying to pick him off base?

The ball usually bounces away when that happens. And if a runner advances because of such a throw, the pitcher will be charged with a throwing error.

But a throw and a pitch are not the same thing. First you asked about a pickoff throw, then you changed the scenario to involve a pitch.

If a runner is hit by a pitch (such as on a steal of home), the ball would be dead and all runners awarded one base from the time of the pitch.

By the way, a runner is not always out if he is hit by a batted ball.

The runner can wait for the pitcher outside and then kick his ***. Or he can realize that life goes on and understand that nothing will happen if he gets hit once again because he'll know it was an accident. Or maybe he can get hurt if the ball catches a soft spot on his body and then leave the game. There are no specific rules that states anything to this regard.

One third possibility is that the ball may bounce far enough from the first baseman and the runner will advance.

The ball is in play and if it bounces off him he can try to advance to second base at his own risk.

There is a story about how Don Drysdale, a Dodger pitcher, hated either Hank Aaron or Willie Mays and not only did he drill him to put him on first, he drilled him when he was sliding back to first on a pick off attempt. Then he spat on the ground just to let him know it wasn't an accident. But if the ball had bounced off him and up the line, the runner could have tried to go to second. Today that would have earned him a 10 day suspension--as it should.

Nothing happens really. The runner is not out if he gets hit by the ball and he doesn't advance a base. The only way he advances is if the ball hits him and bounces away so he is able to get up and advance to the next base.

Nothing, if it is a bad throw it prevents it from getting away from say the 1st basemen, but no one is called out like when a live batted ball hits a runner.

Normally nothing, but if the ball skips away, the runner can try to move up a base.

Because it's boring, never works, slows the game down (a game that is already too slow to begin with) and makes you look like a jerk. Sometimes I even boo when a Phillies pitcher trys to pick someone off.

if a live baseball is thrown by a fielder and hits a baserunner the base runner advances one base. the only exeption to this rule is if a runner is running to first base and he is in fair territory, if a thrown baseball hits him he is out.

If the base runner is hit by the ball on a pickoff attempt and is injured, the ball is dead and the runner is awarded the base he was going back to.

Without all the verbiage, the ball remains live, and runner(s) may attempt to advance at their own risk.

Bob