Per ESPN's Adrian Wojnarowski, the deal includes the Sixers' No. 36 overall pick. Richardson, who joined the Sixers last season through the sign and trade that sent Jimmy Butler to the Miami Heat, will get a fresh start once again with the Mavericks.
Meanwhile, the Sixers receive 30-year-old veteran shooting guard Seth Curry. Last season with the Mavericks, Curry averaged 12.4 points-per-game while shooting 45-percent from beyond the arc.
Last year, the Sixers went into the offseason with the intention of becoming one of the NBA's best defensive teams. Therefore, Philly acquired Richardson with hopes that he could help them reach that level.
Although Richardson's defensive value was as good as advertised, his limited offensive skillset didn't help the Sixers' spacing issues throughout the year. So, heading into the 2020 offseason, Philly switched gears and focused on building a team of shooters.
Considering Richardson only hit 34-percent of his three-point shots last year, it felt like only a matter of time before the 76ers moved on. Sure enough, Daryl Morey, Elton Brand, and the rest of the front office moved Richardson to Dallas in order to acquire Curry, who has drained 44-percent of his three-pointers throughout his career.
The 76ers will now move forward without Al Horford and Josh Richardson, but recently added Danny Green, Terrance Ferguson, and Curry through trades on Wednesday night.
Justin Grasso covers the Philadelphia 76ers for Sports Illustrated. You can follow him on Twitter: @JGrasso_