The plugin MDGetuserfield can show a field from the user database in your content. Download the file and install it as a Joomla! plugin. Under parameters the field to be shown can be selected. The name is shown by default.
Place mdgetuserfield in sprockeds in your content, the specified field will be shown.
This plugin is a simplified version of Getcbfield
Update 1.1.0 Added update server
Update 1.1.1 Small bug fix release