Davis, the top overall pick in the 2012 NBA Draft, was traded to the Mavs last February by the Los Angeles Lakers in the deal that sent Luka Doncic in the opposite direction.
On Wednesday, ESPN cited unnamed sources in reporting the Mavericks sent Davis, Jaden Hardy, D'Angelo Russell and Dante Exum to the Wizards.
In exchange, Washington sent Dallas Khris Middleton, AJ Johnson, Malaki Branham, Marvin Bagley III, plus two first-round draft picks and three second-round selections, according to the report.
The swap will give the Mavericks a first-round pick from Oklahoma City in this year's NBA Draft and a 2030 first-round pick from the Wizards, plus second-round choices in 2026, 2027 and 2029 obtained in prior deals with other clubs.
Several deals came ahead of Thursday's NBA trade deadline, with Milwaukee's Greek star big man Giannis Antetokounmpo and Ja Morant of Memphis the biggest names also expected to be on the move.
The Cleveland Cavaliers made their deal for James Harden official on Wednesday, a day after multiple reports revealed the 11-time NBA All-Star guard was leaving the Los Angeles Clippers for the Cavs in exchange for guard Darius Garland.
"James Harden has cemented himself as an all-time great in this league and he adds another elite playmaker and All-NBA talent to our roster," Cavs president of basketball operations Koby Altman said.
"We're excited about the impact he will have on our group and our championship aspirations. His presence will elevate our offence, create opportunities for teammates and bring valuable playoff experience at both ends of the floor."
Davis, 32, has struggled with injuries for many years. He has averaged 20.4 points, 11.1 rebounds, 2.8 assists, 1.7 blocked shots and 1.1 steals in 20 games for Dallas this season.
His career averages are 24.0 points, 10.7 rebounds, 2.6 assists, 2.3 blocks and 1.3 steals per contest.
The Wizards, second-worst in the Eastern Conference at 13-36, add Davis to a lineup that includes four-time NBA All-Star guard Trae Young, obtained last month in a deal with Atlanta.
The Mavericks, 19-31 and on a five-game losing skid, add financial flexibility plus future draft picks to help rebuild the squad around star rookie Cooper Flagg.