In the bottom of the fourth inning during the Brewers-Braves NLDS Game 4, Brewers third baseman Luis Urias made an unbelievable catch on a foul ball after it ricocheted off catcher Omar Narvaez. Check it out. 

Initial slow-motion replays on the broadcast showed that the ball might have hit the ground before Urías secured it, however, so the umpires went for a very short review. Here's a closer look. 

The umpires immediately came back and the call stood. 

Whether or not that was actually a legal catch by Urías was irrelevant during the review. The play isn't reviewable. Via MLB.com, here's a quick note from the section on what plays are reviewable: 

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  • Catch plays in the outfield: An umpire's decision whether a fielder caught a fly ball or a line drive in flight in the outfield before it hit the ground is reviewable, but fly balls or line drives fielded by a defensive player in the infield is not eligible for review.

This was a fly ball fielded by a defensive player in foul territory in the infield area, so by rule it isn't reviewable. 

One might wonder what they reviewed, then, and the broadcast was given word by MLB officials that they were checking to see if the pop up hit the net behind home plate on its way down. If so, it would've just been ruled a foul ball. 

At the time, it seemed like a huge call. The Braves had just allowed two Brewers runs -- their first runs since Game 1 -- and had the leadoff runner on base. This Adam Duvall pop out was followed by another foul out, this one from Joc Pederson. With two outs, however, the Braves would get a walk, hit batsman and then an Eddie Rosario two-RBI single to tie it. 

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Of course, it still makes one wonder: Had the play been reviewable and had it been overturned, would the Braves have had a much bigger inning?