Sprint is the only one of the big four U.S. carriers that is not offering any Windows Phone 8 devices, but in 2013 that changes. They did offer Windows Phone devices previously, when running Windows Phone 7. The HTC Arrive had so-so sales.
The company is optimistic about Windows Phone 8, but not so excited that they have to hit the holiday season this year. to the point to speed up things and get WP8 devices on Sprint in time for the Holiday season. Besides, the Nokia Lumia 920 is an AT&T exclusive for 6 months anyway. AT&T also seems to be the preferred partner of Microsoft and Nokia, even though the carrier is known for selling the most iPhones.
Next year is the year for Sprint and Windows Phone 8.