How to Frame a Jersey
To frame a sports jersey, start by choosing a shadowbox frame with UV protective glass to keep the colors in your jersey from fading. Additionally, make sure there's at least 1 inch of space between the glass and your jersey to prevent moisture buildup, which can result in mold spots. Then, sew the edges of your jersey to the backing of the frame to keep it from moving once it's in the frame. Finally, insert the backing and your jersey into the frame.
Choose the right frame. To display a sports jersey, use a shadowbox frame, which is a shallow, framed, rectangular box is usually use. Shadow boxes have a glass front that is ideal for displaying and protecting bulky items, because they provide more space between the backing and the glass than a traditional frame does. The inside of the frame will need to have at least 1 inch (25.4 mm) of space between it and your jersey. The typical jersey-size frame is 40-inches by 32-inches. Choose a frame that is stained or painted a color that matches your jersey, and the décor in your home. Look for a shadow box with UV-protective glass. There are certain frames made specifically for jerseys, but they tend to be very expensive. A shadow box with the right dimensions will most likely be much cheaper than a frame made especially for a jersey. Select a backing. Unlike with a regular picture frame, the backing that comes with your shadow box may not be all you need to use for your framing project. For a jersey, typically you need foam backing to provide support (this might come in the frame), and an acid-free archival backing paper to go over the top. You may or may not choose to use matting around the edges for extra effect. A lot of framers choose to use dry mounting to prepare the backing for the frame. This safely attaches the archival paper to the backboard. The backing paper should be a neutral color that complements your jersey. Get the rest of your supplies. For completing your project, you'll also need a measuring tape, an x-acto knife, a sewing needle (embroidery works best), clear thread (like fishing line), and whatever mounting materials you chose to use (specific to the type of backing you're using). You'll probably also want a clothing iron, so that you can prepare your jersey for framing and help the folds to lie flat inside the frame. Prepare your backing. Cut your foam or backing board to shape, using an x-acto knife. The board should be the same size as your frame. Then, place your mounting paper over the top. If you're dry mounting the backing, you should do so now. Cut your foam board insert. If you have enough room inside the shadow box frame, it is a nice addition to insert a sheet of foam inside the jersey, inside the frame. This will provide support and help the jersey to look a bit more filled-out than if you pin it flat to the board. Cut a piece of your foam board into a rectangle the size of the torso of the jersey, and insert it inside. You can sew the backside of the jersey to the board to help secure it in place, or just use a few straight pins. Fold your jersey. Although there are a few different ways to fold your jersey, they all are done so that the major logos and symbols are visible inside the frame. Lay your jersey flat on a tabletop, and fold the sleeves over so that they go downwards. Use an iron to keep the jersey in this position, to prepare it for its life in a frame. Sew your jersey in place. Thread your needle with your clear thread, and begin hand-sewing around the edge of the jersey. Sew around the neckline, at the hem, and the sides and sleeves of the jersey. If possible, sew through the back of the fabric rather than the front, so that the thread is hidden. You are sewing the jersey to the backing, so that it does not move inside the frame. Place the jersey inside the frame. If the jersey is safely secured to the backing and arranged to your liking, you are ready to place it inside your frame. Carefully slide it in, being careful not to move the jersey as you do so. Make sure that the jersey does not touch the glass, as over time the moisture buildup here will cause the jersey to mold. Secure the back of the frame, and you're finished! 
Choose the right frame. Select a backing. Get the rest of your supplies. Prepare your backing. Cut your foam board insert. Fold your jersey. Sew your jersey in place. Place the jersey inside the frame. 