Less has an idea that he has not tried
Cut a piece of Artcare to the size of the frame. The Artcare will be used as the sink-mounting board and the jersey’s center support form.
Lay your shirt/jersey out flat and pin it into shape on the Artcare. Draw your center form into the appropriate shape. Test with regular foam first if you wish. If it works, then use that form to cut out the Artcare.
Before fitting the center support form inside the jersey, use it as a template to cut out the front and back colored face boards. Attach all of the face boards pieces to the Artcare. Fit the center support form into the jersey and test fit into the sink-board, trimming if required. If you have difficulty fitting the center support form into the jersey, vertically cut in it in half, inserting back into place and secure if necessary. Sew the jersey down for additional support if desired.
Install appropriate front and rear spacers and glazing into the frame.
For the brave and well-equipped framer, you could try this with an acrylic support.
Let me know if it works.