We had this happen in a game of mine about 10 years ago:
Play: A1 runs the ball in a sweep to the sidelines. A1 runs past LM, and about 5 yards past the LM, A1 is hit by B1, fumbles the ball, and it bounces right at the LM, he tries to avoid it by stepping out-of-bounds, but only manages 1 leg in-bounds and 1 leg out-of-bounds. The ball bounces on the ground in the field of play directly into the LM's leg in the field of play (ball would have gone out-of-bounds if the LM's leg wasn't there) and then back to the field-of-play where B1 jumps on the ball.
What is the ruling?