Is a running back allowed to toss the football out of bounds to stop the clock?

Question

This question applies to all levels of American football from pee wee football all the way up to the NFL.

If a running back is past the line of scrimmage and is running towards the sideline with the intent of getting out of bounds to stop the clock but his path is blocked by defensive players, can the running back toss the football out of bounds to stop the clock?

I'm not talking about him passing the football over the heads of the defensive players into the sideline, but him tossing it like a softball towards the sideline and angling it a few yards back from his position on the field so its not a forward pass.

Will the ball be placed at the point where the ball entered the sideline and will this stop the clock?

Answer 1

This is illegal and penalized after the 2 minute warning:

NFL Rules 4.7.1 ILLEGAL ACTS

A team is not permitted to conserve time after the two-minute warning of either half by
committing any of these acts:[...]
(d) throwing a backward pass out of bounds;

Outside the two minute warning it is ruled as a ball out of bounds. The ball will be spotted at the point where it crosses the sideline and the gameclock will stop until the ref signaled that the ball has returned to the field of play.

NFL rules 8.7.2 BACKWARD PASS OUT OF BOUNDS

If a backward pass goes out of bounds between the goal lines, the ball is dead (7-6-2-a), and it is next put in play at the inbounds spot. Rule 11 governs if a backward pass is declared dead behind the goal line.

NFL rules 4.4 STOPPING THE GAME CLOCK

The game clock operator shall stop the game clock (timeout) upon a signal by any official or upon the operator’s own positive knowledge:[...]
(c) when the ball is out of bounds;

NFL rules 4.3.2 SCRIMMAGE DOWN

(f) If a fumble or backward pass by any player goes out of bounds, the game clock starts on the Referee’s signal that a ball has been returned to the field of play.

So there is a minimal time gain possible, considering the time it takes for the ref to get the ball when the player is tackled in bounds, at the risk of losing a few yards and possibly the opponents stopping the ball before the sideline and avancing with it (even if it touched the ground in bounds, it still is a life ball)

Answer 2

The above answer is incomplete if not outright incorrect. It's not just that it won't work--doing so would actually make the situation worse.

NFL Rules 4.7.1 ILLEGAL ACTS

A team is not permitted to conserve time after the two-minute warning of either half by committing any of these acts: ... (d) throwing a backward pass out of bounds ... Penalty: For Illegally Conserving Time: Loss of five yards unless a larger distance penalty is applicable. When actions referred to above are committed by the offensive team while time is in, officials will run off 10 seconds from the game clock before permitting the ball to be put in play on the ready-for-play signal unless another rule prescribes otherwise. The game clock will start on the ready-for-play signal. If the offensive team has timeouts remaining, it will have the option of using a timeout in lieu of a 10-second runoff, in which case the game clock will start on the snap after the timeout.

So not only does such an act risk recovery by the defense, it will not successfully conserve time and will in fact make the situation worse as (a) it will take a significant chunk of time off the clock with the; (b) the clock will start on ready-for-play rather than on the snap; and (c) there is a five-yard penalty on top of all that.