I've got my game set up before Dead Beat, so there is a regional commander living in Dallas. I'm going to assume before Dresden becomes a warden and then a regional commander that he dies.
It would make sense. In Dead Beat about 140 Wardens die, hence Harry getting 'drafted'.
That sort of event is going to have a significant impact on the Wardens/forces available to the White Council, and absolutely something to keep in mind when timing events of a campaign. At least if attempting to keep the campaign canon.
-Cheers