Lacy (undisclosed) reverted to the Raiders' injured reserve after getting waived/injured by the team Sunday, Paul Gutierrez of ESPN.com reports.
The Raiders signed Lacy to a future/reserve contract Monday.
Las Vegas elevated Lacy to its active roster from the practice squad Friday for Saturday's game against Kansas City.
The Raiders re-signed Lacy to the team's practice squad Thursday.
The Raiders waived Lacy on Tuesday, Tashan Reed of The Athletic reports.
Lacy signed a contract with the Raiders on Wednesday.
The Bears waived Lacy on Monday, Brad Biggs of the Chicago Tribune reports.
Lacy caught three passes for 26 yards in the Bears' 41-15 preseason loss to the Bills on Saturday.