I've seen the film of this incident more than a dozen times, and I don't see a pause.

The throw is late coming from the infield (regular centerfielder Dom Dimaggio had been replaced the inning before) but Pesky turns and throws to the plate. The throw is off line, a few feet up the third base line, and its by no means a good play, but I have yet to detect a perceptible pause.

That was bad. I still don't understand what he was thinking on that play, but at least the Red Sox got revenge 58 years later.