Odom, a forward for the L.A. Lakers, and Khloé recently have been "talking about rings," says a source close to the couple.
Members of the Kardashian family are neither confirming nor denying the wedding plans or a date. A rep for both stars have declined to comment.
The in-the-works marriage would be the first for Khloé, 25, and Lamar, 29, who had three children with his former longtime girlfriend, Liza Morales. They have a 10-year-old daughter, Destiny, and a 7-year-old son, Lamar Jr. (On June 29, 2006, Odom's 7-month-old infant son, Jayden, reportedly died from SIDS while sleeping in his crib in New York.)