You can uninstall or removes an installed gearman-worker package itself from Debian 7 (Wheezy) through the terminal,
$ sudo apt-get remove gearman-worker
If you would like to remove gearman-worker and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove gearman-worker
If you use with purge options to gearman-worker package all the configuration and dependent packages will be removed.
$ sudo apt-get purge gearman-worker
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove gearman-worker