A Foul Ball off the Protective Netting - Wall Physics

Atlanta had to wait just a bit longer for Bryce Harper to make the third and final out of NLDS Game 2 vs Philadelphia after HP Umpire Nic Lentz ruled an earlier foul fly ball by the Phillies batter dead and out of play, with the baseball contacting the protective netting behind home plate before Braves catcher Travis d'Arnaud could catch it.

The primary clue of a ball having struck a wall or scraped a fence is whether the ball suddenly changes direction when coming back toward the playing surface. Physically speaking, as well, projectile dymanics as well as spin rate and wind speed + direction all play a role in officiating this play.

In this case, video doesn't appear to show where exactly the ball was relative to the boundary—Lentz's position along the fence-line is the optimal angle for officiating this play and better than any TV camera.

For that reason, Replay Review ultimately ruled "call stands" due to a lack of clear and convincing video evidence to prove either potentiality. A few pitches later, Kenley Jansen struck out batter Harper to end the game.

Video as follows:

Alternate Link: Lentz's foul ball off the screen call gets upheld on boundary challenge (CCS)