Trademark law does not automatically extend to the use of a color / combination of colors used in the cloth of clothing.
But if you are copying the jersey, without the logo, that might make the goods confusingly similar.
You are allowed to have a green and yellow shirts. But if you make it identical to the Oakland As jersey and start selling them, expect a C&D letter at a minimum.
Consult with an attorney in your area.
This is by far too fact intensive of an inquiry that cannot be answered in a forum such as this. If you consult with an IP attorney, which I highly recommend, let that person evaluate it in person.
This is not to be construed as legal advice, and I am not your attorney, A conflict check and engagement letter would necessarily be required before any retention or attorney/client privilege exists.
This can and will likely be problematic because these trademark owners have an interest not just in their logos and text brands but also in what we call trade dress (see link below for more detail on this). This can be among other things the color schemes and configurations of their brand. For example, you do not have to call yourself McDonald's, but if you chose to set up your fast-food restaurant to look like a McDs using the same color chairs, floor designs, signage, etc they will have a claim against you.
Obviously, no one owns specific colors outright, so the context matters a lot. But it is clear from your narrative that you intend on selling a product your consuming market will recognize as possessing team colors.
I suggest you discuss your plans and objectives over with a lawyer before jumping in. Most of us here, including myself, offer a free phone consult.
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No. Your shirts would violate trade dress protection if you produce and sell them without a license. If the design and colors would lead consumers to believe that the shirts are associated with specific teams, they would violate trade dress law even if you do not mention the name of the team or use its logo.
Here is the rule of thumb: Anytime someone attempts to profit by associate his products or business with famous celebrities, sports franchises, colleges, products, etc., this probably violates intellectual property law and unfair competition law if this is done without a license.
Of course, if you want to make original shirt designs with various colors, you are free to do so. No one monopolizes any particular color. But you cannot arrange the colors and designs in a way which would remind consumers of specific sports teams.
You're greatly overstating the trade dress restrictions on the colors used on your shirts. You can lawfully make your clothes any single color, any combination of three, or four, or five colors -- and any combination of two colors so long as the way you present that combination is not likely to confuse consumers into falsely believing a sports team makes the shirt or is somehow associated with the shirt. A black tee shirt with a yellow collar, for example, would not infringe the Pittsburg Steeler's trade dress rights in the appearance if its uniforms. But a black and yellow stripped shirt, or a black tee shirt with yellow stripes on the sleeves would. I think you're trying to come as close as you can to creating shirts that people will buy because they like the association the shirt creates with a sports team without you getting sued for infringement. Why don't you create your own brand instead of trading off other company's marketplace efforts?
The above response is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.