Thanks to Everett for the pointer. There is a Microsoft SQL Server ODBC driver for Linux available. This was news to me. Version 1.0 was released on March 6, 2012. Connectivity with SQL Server 2012 is supported.
Here is a link to the driver: Microsoft SQL Server ODBC driver for Linux
Supported operating systems are 64-bit RedHat Linux 5 and 6. I will be trying this out on CentOS.