As far as I know, *nothing* is measured on the balls each game prior to use. Storing balls in the humidor prior to use keeps the environmental factors constant.
Barton L SmithAs far as I know, no one other than me and Lloyd Smith have measured seam heights, and I think we're the only ones to measure widths, and only on about 100 balls several years ago. MLB does not check anything on the balls at the stadium prior to use, I don't believe.
