According to ESPN, the Raptors and Bucks are close to a deal involving Carlos Delfino, Roko Ukic, Amir Johnson and Sonny Weems.
Johnson can't be dealt in a package deal until Aug. 23rd though, so this trade wouldn't be official until early next week and Weems cannot be moved until October unless he is traded one-for-one.
Unless I'm missing something CBA-wise, this deal can't be done until early October.

NBA front-office sources told ESPN.com on Monday that the Raptors are actively trying to move swingman Carlos Delfino in a sign-and-trade arrangement.
One option that has materialized, sources said, is a deal with the Milwaukee Bucks on a swap that would send Delfino to the Bucks for power forward Amir Johnson, which would require Delfino to agree to terms on a new deal spanning at least two years.

Johnson was acquired by Milwaukee in late June as part of the three-team swap with San Antonio and Detroit that routed Richard Jefferson to the Spurs and was briefly projected as the Bucks' new starter at power forward after Charlie Villanueva left in free agency to sign with Detroit.

But Milwaukee was able to sign Hakim Warrick to a one-year, $3 million deal earlier this month after the Grizzlies unexpectedly withdrew their qualifying offer to Warrick, turning the restricted free agent into an unrestricted free agent.

Johnson is an athletic shot-blocker with an expiring contract. He would add more defensive muscle to a team that still needs that in large doses. It's hard to see Johnson getting many minutes though, with Reggie Evans slotted ahead of him at the backup power forward slot.
Johnson isn't the bruiser Evans is, but he's a passable rebounder and the most gifted shot-blocker on the team now.

Delfino was no longer needed now that the Raptors beefed up their backcourt by adding Jarrett Jack, DeMar DeRozan, Marco Belinelli and Antoine Wright.
He is likely a better player than the latter two, but wanted too much money on too long a term.
The Raptors are trying to keep as much cap flexibility as possible for next summer, when Chris Bosh becomes a free agent.
Ukic was also buried on the depth chart in Toronto and was not going to emerge here.
He has yet to put his game together at the NBA level but has some promise.
How many minutes he gets in Milwaukee depends on how the Ramon Sessions saga unfolds.
He's certainly not getting any time if Sessions, rookie Brandon Jennings and veteran Luke Ridnour are still on board.

More details as they emerge.