I have seen a player wear the wrong uniform number in a game, but not the wrong uniform.
Junior Lake made the fashion faux-paux during the Pittsburgh series. He came out wearing the wrong uniform.
How could that happen?
Why didn't anyone notice?
The clubhouse attendants get the lockers in order for the players. The equipment managers pack and unpack the uniforms and place them in the lockers. Everyone is supposed to be on the same page.
So how could Lake wear the wrong uniform?
A prank. The press reports afterward did not indicate Lake was made the butt of a brutal joke.
Did the equipment people put the wrong uniform in Lake's locker? Well, yes, Lake had to have access to it. There may have been two uniforms in his (and everyone else's) lockers.
Why didn't the players next to Lake tell him he was suiting up wrong?
And this gets to the inner circle of a baseball locker room. Fans hear from the press (and various former players) that the locker room is the players room. Team leaders have great control and influence over the culture and professionalism of this fraternity house. A good, tight, professional, no nonsense locker room is good - - - the Yankees have maintained one for decades.
So besides Lake dropping the ball on his uniform snafu, so did the unnamed leaders in the locker room. One can imagine that the Cubs locker room may be like the ante room of a funeral home - - - the players expect the worst this season after the brutality of the past three campaigns. So there may be a lack of focus during the pregame. Everyone may be just looking after his self (because of all the press about the youngsters on the way.)
Or maybe many of the Cubs are blind. (Which could solve the riddle of the horrible RISP problem.)
The Cubs did not need another example of being a baseball laughing stock. But in pure Cub fashion, this team seems to gravitate towards badness like a moth to a light bulb.