Johnson agreed to terms with the Rams on Saturday, Aaron Wilson of KPRC 2 Houston reports.
Johnson caught two passes for eight yards and a touchdown during the 2023 regular season.
Johnson secured two of three targets for eight yards and a touchdown during Sunday's 21-20 victory against San Francisco.
Johnson was elevated from the practice squad by the Rams on Saturday.
The Rams waived Johnson on Tuesday, Stu Jackson of the Rams' official site reports.
The Rams signed Johnson on Tuesday.
The Raiders waived Johnson on Monday.
The Raiders signed Johnson to a reserve/future contract Wednesday.
Johnson was signed to the Buccaneers' practice squad Monday.
Houston waived Johnson on Tuesday, Jonathan M. Alexander of the Houston Chronicle reports.