Jettisoned space junk -- how big?

"Chuck Stewart" wrote
But the main point, which thousands of forum and
blog pundits seem to have missed and keep on
missing with a vengeance, is that it's perfectly
*feasible* for the ball to return at some later
date and impact ISS with a relative velocity
orders of magnitude greater than the one the
cosmonaut imparted to it.

I've heard this said,
but I haven't seen
any proof of it.