Thomas, 33, played just 18 games with the Mavs last season before leaving the team to be with his ailing wife. He never disclosed his wife's illness, but she is apparently doing well enough for Thomas to return to the league. Both sides handled last season's situation in good faith and want to continue the relationship. ESPN.com's Marc Stein first reported in late July that Thomas and the Mavs were working on a deal.
"If all goes well, we'll reach an agreement," Myers said Monday.
The 6-foot-10, 240-pound Thomas provides an immediate need for Dallas, which has no true power forward on the roster behind Dirk Nowitzki.
Thomas has career averages of 11.5 points and 4.1 rebounds in 13 NBA seasons. He is a career 36.9-percent shooter from 3-point range. Myers said Thomas is not talking with any other teams.
If the Mavs and Thomas reach a deal, Dallas' roster will hit 14, leaving one spot available.