Why wasn't Arthur J. Nascarella credited for his role

The cop that cruelly badgers Gabriel (Adam Trese) and busts him when Dante (Michael Rappaport) sets him up to be pulled over driving his own car with his drugs in it was none other than ex-NYC police detective Arthur J. Nascarella, veteran actor of gangster roles and ex member of the Sopranos cast. He's perfect in this role since that was what he did for a living before making it to the film business. You might remember him also as mob boss. Don Santalino in WiseGirls with Mira Sorvino and Mariah Carey.