Steelers Practice Jersey Help

[sprint23]

I just purchased this jersey. The seller said that he won it in a charity auction. All the tagging seems correct for a 2001 Steelers practice jersey but there was no #43 on the roster in either 2001 or 2002. Polamalu joined the team in 2003. I like the jersey and believe I got it for a good price even if it's just to wear but am curious as to exactly what the history behind the jersey may be. Any thoughts are appreciated. Thanks.