Oops forgot the link of an example Sports Jersey Display Case Frames
Some Wood Art projects my wife and I have finished. Examples
The one in your link has mitered corners. That obviously works, but you could also make a frame with rail and style bit set and make it more like a cabinet door. Most rail and style bit sets will require 3/4" thick material. This will make the display much heavier than the one shown.
If you want to keep it lighter in weight, for the door you could use 1/8" glass with corner molding that is sold at Home Depot, Lowes, Menards or other lumber yards. This will typically come in 3/4" x 3/4" x 96" strips. It will have an inside dimension of 1/2" x 1/2". You could simply cut to the proper length and miter the corners. Then glue and pin the corners from the sides with a brad pinner. Most of the weight will be in the glass. The problem with keeping it this light weight is that the frame around the glass won't be real sturdy or strong. That is why I initially suggested a rail and style method. The rail and style frame will end up being much sturdier and easier to glue up. It will allow you to use either 1/8" or 1/4" glass. If you go to a glass store, they will be able to get you glass that will block UV light that could damage your jersey. You simply use glass instead of a raised panel. There are bit sets that are designed for glass panels, or you can simply saw off the inside lip of other bit sets. The advantage of the ones designed for glass doors, is that they will also make up matching wooden glass holding strips while making the rails and styles.
Another advantage of the rail and style method is that you can use the cabinet style cup hinges. This allows you to make the display case with no visible hinges.
The back of the cabinet could be made of 3/4" thick boards with a rabbited back to accommodate a 1/4" thick plywood or MDF panel. If you don't want any visible corner joints, you could use a locked miter bit for joining the sides to the top and bottom. This will give you extra gluing surface to join these pieces together. This method will allow you to make the display case as deep or as shallow as you want.
Be sure to provide some method of mounting the display case to the wall. I like to use a keyhole bit and make one (or two if you want to keep the case always level) long keyhole(s) across the top. Then you simply place one (two) screws in the wall, slip the head of the screw into the key hole and slide the case over until it stays level. This method eliminates any visible mounting means.