Its up to the Cubs, not MLB, until the game begins. It wasn't raining at the time so it would have been really hard to justify them not starting. Actually with this being the last time into town for the Cards, and the season starting into the stretch run, the umpires are more or less under the gun from MLB to play. If this had been back in April, its the Cubs call. Now with looking at having to work around the 20 days in a row max in the BPA its a no brainer looking to get a two hour window they are playing per MLB. That's relevant now once the game has started; it was the Cubs' decision, not the umpires' to try to play the game rather than calling it before it started. With it being the last time the Cards are in and the time of the season it isnt the Cubs call to start. MLB dosent want the headaches of dealing with the players association to get a waiver so they can play more than 20 days in a row. The supposed two hour window they had to start guaranteed a start and the chips would fall where they may.