This is the Herschel Walker version of the 1991 Ace Novelty Co.'s trading card and pin. The card enclosed appears to be a 1991 Pacific #299 of Walker. Perhaps the two companies had some sort of licensing agreement, or maybe one owned the other, I'm not sure.
The pin has a photo of Herschel on the front. There is a pin back on the reverse to allow it to be attached to clothing and in addition, each players stats for that season are engraved on the back of the pin.
I discovered the stats on a loose pin of Walker, that I came across, in addition to this example, which has not been removed from the packaging. This is the second year of these items put out by the Taiwanese company, Ace Novelty. 1990 was the first year.