The Mavericks and Samuel Dalembert continue to negotiate a free-agent deal, and a source said Saturday that both sides seem optimistic that an agreement will be reached, and that they are inching in that direction. Dalembert remains the best center available on the open market. There may be others available via trade. But the more likely possibility is that Dalembert and the Mavericks find a common ground. The Mavericks have a starting job to offer. Dalembert has a strong history as a good rebounder and defender. It makes sense. The Mavericks still have a few dollars left under their salary cap, even after agreeing to terms with Monta Ellis for a touch over $8 million next season. The backcourt, for the most part, seems set.