With all the news about "Deflategate" swirling around, it surely must have crossed your mind at some point over the last few weeks whether something similar could happen in MLS.
Short answer: no.
The main reason is that both teams play with the same ball, so any under- or over-inflated ball would be noticed right away by the players and/or one of the officials, and would be swapped out.
But the topic got us thinking about match balls, in general, and the specific air pressure -- in pounds per square inch (PSI) -- of an MLS match ball, in particular. So, here is the official match ball policy, per the Match Operations section of the 2015 MLS Competition Guidelines:
SOCCER BALLS - The home Club will supply the visiting Club with fourteen (14) official Match balls (which can be previously used Match balls) for pre-Match warm-ups, and will supply the officials with a minimum of twelve (12) official Match balls.
When inflated, each soccer ball will not exceed more than fourteen (14) ounces/psi and no less than twelve (12) ounces/psi. MLS prefers that balls be inflated to thirteen (13) ounces/psi.
All Match balls will be delivered to the locker room of the officials (referees) at least ninety (90) minutes prior to kick-off to pass inspection.
Replacement balls needed during the Match will be provided if necessary and must be inspected by the fourth official prior to it being used in the Match.
All Match balls in the possession of the officials will be returned to the home Club after the Match.
Coincidentally, there was a deflated soccer ball this past weekend in MLS. In the 10th minute of Sunday's New York derby match (photo above), the ball suddenly went soft, and after the players complained, Red Bulls right back Chris Duvall kicked the ball out of play to allow referee Alan Kelly to inspect it and discover the puncture.
A new ball was immediately delivered. Play on.