Look, everything is very simple. First I've sorted playernames table by commentaryid. As I think, commentaryid 900000 means that player is not commented. Now we are going to the bottom side of the table and search surnames starting from HI-. There we have:
923573 Hiariej
923574 Hibbert
923580 Hierro Ruiz
923581 Higdon
923582 Higginbotham
923583 Higgs
923584 Higuaín
923587 Hildebrand
923590 Hills
923592 Hilton da Silva
923596 Hird
923598 Hirschfeld
923602 Hlinka
You can see the gap between 923598 and 923602. I thought that Hitzlsperger have to be after Hirschfeld, so the probable commentaryid's for him are 923599, 923600 and 923601. After that I've edited existing assign for Hitzlsperger (in my case it was 917504 - one for all created players). I've tried 923599 and 923600 and the last one was correct. That's all. The only question is why other players (I've created Alex de Souza for Coritiba and Thimotee Atouba for Las Palmas) don't have such problems and will some other players have the same difficulty. I've noticed that problem just because I remember that Hitzlsperger had commentaryname in previous versions but of course I don't remember every player with commentary name.
So asking your question - I've never seen this ID, just use a little brain to cope with this problem.
And I don't know why didn't he apper in your DB. Yes, as I stated in my thread about squad updates, I've managed to export changest from the squad update to the main DB. Now I have updated rosters as original DB.
Also there is another interesting thing. I've created some more players, but deleted them soon. Now I have empty assigns into the playernames table (just commentaryID and nameID without name).
I think it's not easy to explain everything on fingers, so here is my DB. You can download it and see everything personally.
http://depositfiles.com/files/4xpkaakij