Saints place fullback Johnson on injured reserve
Johnson, whose knee injury shelved him for New Orleans' previous game at Carolina, played in seven games this season with one start.
The Saints needed Johnson to play a regular role while fellow fullback Erik Lorig, who is now healthy, worked his way back from a preseason ankle injury.
Johnson carried eight times for 22 yards and caught two passes, including a 13-yard touchdown reception.
Becton is a second-year pro out of Virginia Tech who played in one game last season with San Diego.
Becton's signing comes after right tackle Zach Strief played through a back injury at Carolina.
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