The Dallas Mavericks are cautiously engaging in contract negotiations with Andrew Bynum after meeting with the free-agent center and his agent at a Dallas hotel Wednesday morning.

"They had a nice visit with our doctors and we had a lunch," Mavs president of basketball operations Donnie Nelson said. "Beyond that, the negotiations are ongoing."

The Mavs were the third franchise Bynum and agent David Lee met with this week, following the Cleveland Cavaliers and Atlanta Hawks. Sources told ESPN.com's Marc Stein that Cleveland offered an incentive-laden, two-year, $24 million deal, including a team option for the second season, to Bynum, a 25-year-old with a history of significant knee problems who sat out the entire 2012-13 season for the Philadelphia 76ers.

Sources told Stein that $6 million of the $24 million offered by Cleveland is guaranteed. Bynum would be forced to reach a variety of incentive benchmarks to collect the full $12 million in Year 1, according to sources, while Year 2 was pitched by Cleveland as a team option year.

Yet it remains unclear how much guaranteed money Dallas will be willing to offer Bynum in a multiyear deal after launching the evaluation process in earnest with Wednesday's meetings. ESPN.com reported Tuesday that the Cavaliers regard the Mavericks as their only legitimate competition for the former All-Star's services.

Bynum, however, has resisted Cleveland's push for a quick answer, leading to the belief that he would rather land in Dallas.

Yet the combination of what is expected to be a higher overall guarantee from Cleveland and the success Bynum had playing for Mike Brown in Los Angeles would appear to have nudged the Cavaliers into the lead for his services.

The Mavs, who targeted Bynum after Dwight Howard decided to sign with the Houston Rockets, continue to proceed with caution while evaluating the medical risks of signing the former All-Star big man.

"At this point, we're having a medical discussion," Nelson said. "We'll have an opportunity to again get with him and his agent and better understand the risks involved and make a good decision for our franchise. We talk to his agent all the time. We're in the process of gathering information."