Case Play 2019-2 - Fly Ball off Player & Wall [Solved]

In the midst of Boston's Memorial Day win over Cleveland, Red Sox batter JD Martinez's fly ball to deep right field wound up in the fair territory bullpen beyond the outfield wall, ruled a home run by 1B Umpire Gabe Morales. With replays indicating the ball caromed off the wall, then deflecting off Indians right fielder Oscar Mercado's glove, and finally landing out of play, was HR the correct call?

Was this a home run or a different base award?

The Play: With two out and none on in the bottom of the 6th inning of Monday's Indians-Red Sox game, batter Martinez hit a fly ball to deep right field that struck the top of the outfield wall, bouncing back toward Indians outfielder Mercado. As Mercado approached the wall, the ball then deflected off the outfielder's glove and fell out of play, into the bullpen beyond fair territory.

Case Play Question: Was the crew's ruling of home run the proper call, given that the batted ball in flight first struck the top of the outfield wall before appearing to bounce over the warning track where it made contact with the fielder on the playing field, finally falling out of play beyond the fence?
Related Post: Replay Review, Ground Rules, and Levi's Landing (9/1/17).
Related Post: 2B Bounding Ball Over Ground Rules-Less Kauffman (7/22/15).

Case Play Answer: By rule, a fair ball passing over a fence at a distance of 250 feet or more is a home run, but a bounding fly ball entitles the batter and runners to two bases. The MLB Umpire Manual further clarifies that a fair fly ball that strikes the top of the wall and bounces over the wall shall be ruled a home run, while a fair fly ball that strikes the top of the wall and bounds back into play shall be live and treated the same as a fly ball that hits off the wall and rebounds back onto the playing field.

Jose Canseco's HR assist is a different play.

Thus, the fly ball is treated as rebounding back onto the playing field, whereupon it is deflected by a fielder and then goes out of play. The resulting award shall be two bases. Had this play gone to Replay Review, the proper decision would be to overturn the on-field ruling and apply the two-base award from the time of the pitch, for the ball was not in flight when it was deflected by the fielder out of play.

Had the fly ball first hit the player, then deflected over the wall, in flight, it would have been a home run. The determining factor is what the ball first struck and, secondarily, what happened to the ball after it hit the outfield wall (e.g., bounded back into play vs. bounced over the wall and out of play).

Official Baseball Rules Library
OBR 5.05(a)(5): "The batter becomes a runner when—A fair ball passes over a fence or into the stands at a distance from home base of 250 feet or more. Such hit entitles the batter to a home run when he shall have touched all bases legally."
OBR 5.05(a)(8): "The batter becomes a runner when—Any bounding fair ball is deflected by the fielder into the stands, or over or under a fence on fair or foul territory, in which case the batter and all runners shall be entitled to advance two bases."
OBR 5.05(a)(9): "The batter becomes a runner when—Any fair fly ball is deflected by the fielder into the stands, or over the fence into foul territory, in which case the batter shall be entitled to advance to second base; but if deflected into the stands or over the fence in fair territory, the batter shall be entitled to a home run."
OBR 5.06(4)(A): "Each runner including the batter-runner may, without liability to be put out, advance—To home base, scoring a run, if a fair ball goes out of the playing field in flight and he touched all bases legally; or if a fair ball which, in the umpire’s judgment, would have gone out of the playing field in flight, is deflected by the act of a fielder in throwing his glove, cap, or any article of his apparel."
MLBUM 9: "Unless provided otherwise by local ground rule, a fair fly ball striking the top of the outfield wall and bounding back onto the playing field shall be treated the same as a fair fly ball that strikes the outfield wall and rebounds back onto the playing field."
MLBUM 9: "Unless provided otherwise by local ground rule, a fair fly ball striking the top of the outfield wall and bounding over the wall shall be ruled a home run."
MLBUM 20: "If a fair fly ball is deflected in flight by a fielder and then goes out of the playing field in flight over fair territory, it is a home run."
MLBUM 20: "If a fair ball not in flight is deflected by a fielder and then goes out of play, the award is two bases from the time of the pitch."
Fenway Park Ground Rule: "Batted ball in flight striking left of line in right center field and bounding into bullpen: Home Run."

Video as follows:

Alternate Link: JD Martinez's deep fly ball off the wall and player leaves the field (BOS)