Tagged as a youth large (16/18). Size 18 is a modern youth XL, so it will very likely fit a men's small. It basically has the same dimensions of a mens medium t-shirt.

Reebok was the NFL Jersey supplier from 2001 on, so this was very likely made in 2000, Simon's rookie season.

fabric pulls on sleeves (a very common issue with these jerseys), otherwise excellent clean condition