Hey man, Here are my initial design ideas for your new branding...
#1 plays off the Upper Deck of a stadium idea. #2 is an old-school script design. This one would be more versatile as far as looking great at smaller sizes. I also thought it might be cool to incorporate some classic pinstripes with this one, perhaps like this: #3, #4
For either one of these, we could also add a grunge/distressed texture so that shirts and other things would have a cool vintage look. I will post those next!
Feel free to comment on these in the meantime. Thanks!
Here is a possible 3-color silkscreen option for shirts and other merch: #5... It could also easily be a 2-color with the green shirt showing through for the brighter green, making for a really affordable and easy print.
Here is another idea, in case you are not requiring the entire name in your main logo: #7, #8 It might be smarter for recognition to just be known as 'Upper Deck'.
Are you wanting to incorporate any other aspects into the design besides baseball? Maybe other sports, or maybe something about your location (Palm trees? Water?, etc.)