Counterfeit Jersey's come in different forms... There are Chinese versions, and Korean versions.  Like watches they will vary in quality and ability to match authentic.... I frequent China and understand intimately the differences between knockoffs and authentics.

 I recently purchased NFL jersey.  The seller markets that it is a Premier, which is fabricator that custom makes jerseys for the actual players standards.  This quality is not a replica, or authentic... its the real mccoy.  Premier is a custom jersey fabricator, and make all jerseys regardless of brand.  The material is like iron, the nylon usually doubled and sometimes triple stitched.  My Mike Alstott jersey is just that....

I recently bought a very good fake-authentic quality, marketed as premier for under $40.  The price was too good, but the quality appeared good, so what the heck.

The Tags are good fakes, complete with hologram, same as purses and other products purchased in China and Korea, they are very close to original.  If you have an original, however, you can see subtle differences in registration of the tags, fonts and type set.  Example, I once saw a tag for Walmart in USD, which listed a sweatshirt for $386.00.  How did I know it was fake? lol.  Aside from no Sweatshirt in Walmart cost 386.00, they seldom end in even dollars.  Asians don't understand this however, b/c their currency is usually only valued at 10ths of a RMB or Yen or Yuan.  So Holograms and tags are not a give away.

However, good indicators if you don't have a sample to compare, is usually the logo and how it is placed or located on teh collar.  Fakes will be on a normal high quality collar, but the V-neck will not have jersey reinforcement at the bottom and the NFL shield may be slightly distorted.  Difficult to tell, but to a trained eye, thats the give away.

Second the numbers on a good fake will be Z stitched, but the nylon applique will not be finished.  The threads will be evident.  Granted these can be remedied with a lighter and carefully melting them from edges, but an authentic will be pretrimmed prior to sewing. 

There are some great tailors in Asia, and the textile world is ever expanding.  Your licensed wear is probably coming from asia either finished or raw material, and the markup is phenomenal.  An NFL department store jersey will cost the retailer no more than $3 USD EXW from factory... so deciding to buy an authentic or a fake-authentic is a decision the buyer has to make, and justified or not, somebody is getting ripped off its your call who.

If the sewn on numbers are your goal, and a price thats reasonable, then a fake is good call.  If you are wanting to support your next draft pick, goto the Prostore.

All the best, and Go Colts in Superbowl XLIndy...