His hand, which was far from his body, stopped the ball, which was going towards an open goal/Krul. Stonewall penalty.
His hand was in a 'natural' position for getting him self off the ground, it wasn't placed there just incase a shot came it's way. Until humans evolve into a more streamlined mammal, you'll find that people cannot keep there hands 20cm from there cock at all times.
I would have given a penalty as you could say he could have done more to quickly move out of the way (debatable), but I wouldn't say it was stonewall.