Zeller gives the Bucks a solid backup center for the playoff push. The deal gives the Nets a chance to further replenish their future pool of draft picks.
The Bucks will send the 2018 second-round pick to the Nets should it fall between 31 and 47 in the draft. Otherwise, Phoenix will receive the pick as part of the Eric Bledsoe trade. If the Bucks pick doesn't convey in 2018, Milwaukee will send its unprotected second-round pick in 2020 to Brooklyn, league sources said.
The Nets have $3.5 million in salary-cap space available, as well as a $6 million disabled player exception from the season-ending Jeremy Lin injury.
Zeller, 28, will compete for minutes behind starting Bucks center John Henson. Zeller has averaged 7 points and 4.6 rebounds in 2017-18. He has played with Cleveland and Boston in his six NBA seasons.
Vaughn, 21, was the 17th overall pick in the 2015 NBA draft, but has been unable so far to get traction in the league. He has averaged 3.1 points in two-plus seasons.