CHICAGO — The first inning of these NL Division Series games between the Chicago Cubs and Milwaukee Brewers have been absolutely wild.

Both teams have scored in the first inning of every game in this series, including a combined five runs in Wednesday night’s Game 3 at Wrigley Field.

The Cubs scoring four runs was a veritable offensive explosion, but what occurred in the top of the first had their fans up in arms.

[MORE: What we learned in Cubs’ nail-biting Game 3 win]

The Brewers quickly put two runners on against Cubs starter Jameson Taillon with one out. Milwaukee catcher William Contreras came up to the plate and promptly skied a pop-up into the air on the infield.

The ball landed 60 feet up the first-base line, and since the entire Cubs infield converged on the ball, the Brewers’ runners were able to advance without a throw.

Here’s the full play:

Of course, that play led to a Brewers run, as the next batter, Sal Frelick, hit a sacrifice fly.

So, why wasn’t it ruled an infield fly and Contreras automatically called out? It’s very possible the Cubs could have escaped the jam without a single run scoring if so.

Here is the definition of an infield fly, per MLB:

“An infield fly is any fair fly ball (not including a line drive or a bunt) which can be caught by an infielder with ordinary effort when first and second or first, second and third base are occupied, before two men are out.”

The key part of that phrase is “ordinary effort.”

On this particular pop-up, it’s hard to argue any Cubs defender would have caught it with “ordinary effort” once first baseman Michael Busch lost it in the sun.

Busch immediately threw his hands up when the ball was hit, forcing Cubs second baseman Nico Hoerner, shortstop Dansby Swanson and catcher Carson Kelly to start sprinting toward the ball — which ended up helplessly landing on the infield grass.

Umpire supervisor Larry Young was on site at Wrigley Field and spoke to a pool reporter about the play.

“The basic thing that we look for is ordinary effort,” Young said. “That’s in the rulebook. We don’t make that determination until the ball has reached its apex — the height — and then starts to come down. When the ball went up, initially everybody thought it was going to be ordinary effort, even the batter (Contreras). He wasn’t too sure if he was going to run, then he started to run.

“When it reached the height, the umpires determined that the first baseman (Busch) wasn’t going to make a play on it, the middle infielder (Hoerner) raced over and he wasn’t going to make a play on it, so ordinary effort went out the window at that point.”

The Cubs didn’t disagree with the call.

“The umps got it right,” Cubs manager Craig Counsell said after the game. “You have to have a player that’s going to catch it to call infield fly. We never had a player really close to catching it. So, right call. I was hoping they made the wrong call — they did not.” 

Hoerner said he’d never seen a play like that, but he also agreed the umpires made the right call.

The Cubs made that play look at least somewhat obsolete by scoring four runs in the bottom of the first, which ended up being enough in a 4-3 win. But in a potential elimination game, every run matters for the Cubs.