The Cubs and Cardinals will be playing in London on Saturday and Sunday. As has been in the case in all previous London-based MLB games (and most non-USA/Canada games), the game will feature series-specific uniform advertising.
The Cubs are replacing their usual walking bear left-sleeve patch with an ad for Advocate Health Care (shown above). Here’s another shot that gives a better sense of how it will look on the players:
The Cardinals will continue to wear their existing Stifel sleeve ad, and both teams will wear Capital One ads on their batting helmets. I haven’t yet seen any visuals on the helmets, but they will presumably look like the ad-clad helmets we’ve seen for other non-USA/Canada games.
In addition to the ads, both teams will also wear MLB World Tour patches on their caps and jerseys (which you can also see on several of the Cubs in that last shot).
(My thanks to Adam Foxman for the second photo.)