According to the sources, the Cavs are mostly worried about Dallas in the Bynum chase and thus have tried to construct an offer that the Mavs can't touch while likewise doing no harm to their long-planned bid to try to bring LeBron James back to Ohio in free agency in the summer of 2014.
The Cavs would hold a team option in the second year of the proposed deal, which they feel would provide the needed flexibility to keep Bynum if he bounces back in a big way or part ways with him if Bynum's famously shaky knees -- he had arthroscopic surgery on both knees in March -- don't hold up.
Yahoo! Sports had earlier reported the details of Cleveland's offer.
Cleveland sees the possible addition of Bynum as a unique opportunity, given how rarely former All-Star centers become available -- especially at age 25 -- as well as achievable for a franchise not exactly known for its free-agent pull.
Bynum played one season in Los Angeles under Cleveland coach Mike Brown and had his best season, averaging 18.7 points and 11.8 rebounds. Over the past four seasons, Bynum has averaged 14.7 points and 9.5 rebounds.
ESPN.com senior writer Marc Stein contributed to this report. Information from The Associated Press also was used.