The Wizards opted not to re-sign Diallo after his 10-day contract expired Friday, Keith Smith of Spotrac.com reports.
The Wizards recalled Diallo from the Capital City Go-Go of the G League on Thursday.
Washington assigned Diallo to the G League's Capital City Go-Go on Tuesday.
The Wizards signed Diallo to a 10-day contract Tuesday, Shams Charania of The Athletic reports.
Diallo was waived by the Wizards on Saturday.
Pistons head coach Dwane Casey acknowledged Tuesday that Diallo (ankle) likely won't be available to play again this season by the time he's re-evaluated in 3-to-4 weeks, Omari Sankofa II of the Detroit Free Press reports.
Diallo suffered a Grade-2 ankle sprain and will be re-evaluated in 3-to-4 weeks, Keith Langlois of the Pistons' official site reports.
Diallo (ankle) has been ruled out for Tuesday's game against the Wizards.
Diallo supplied 23 points (10-15 FG, 0-1 3Pt, 3-6 FT), three rebounds, two assists and three steals in 33 minutes off the bench during Monday's 117-106 loss to Charlotte.
Diallo (illness) was left off the injury report for Friday's game versus Charlotte.