Given that truly high-value collectibles are scrutinized and valued for as "pristine" a condition as possible, I'd warn any customer looking to retain value against altering the jersey.
If they want to investigate further, then contacting a reputable sports memorabilia consultant would be a wise move.
This falls under the umbrella of "do no harm" framing practices.
Altering the jersey for the sake of aesthetics may harm its potential future value.
I framed a knitted Canucks hockey jersey.
There was a stitched patch on the front that could not also be shown with the name on the back being the side displayed.
(Double sided framing was not in the budget).
The customer had the idea to unstitch the patch and re-apply it on the back.
I told them if the jersey may have value now, or may gain value in the future, doing this would completely de-value its collectibility.
She said she didn't care about that, so we did it.