Sean Payton confirmed the signing on Monday.
When asked what he liked about Marshall's workout, Payton said, "He moved around well. He's smart, he's experienced, he's someone that's been in a number of systems. And overall he had a good workout. He's got good length and size. He's another big target."
Both receivers auditioned for the Saints this past Tuesday. And sources told ESPN's Adam Schefter that the Saints were impressed enough with Marshall's workout that they considered signing him even before Bryant tore his Achilles in practice on Friday.
Asked if the Saints were looking for a certain "type" receiver since Marshall and Bryant are both bigger red-zone targets, Payton said, "Yeah, I thought size was important, but experience and someone that we felt had strong hands."
This will be Marshall's fourth team in two years and the seventh of his 13-year career after he was released by the Seattle Seahawks on Oct. 30 and by the New York Giants in April. But if he sticks in New Orleans, the 34-year-old will finally have the chance to play in his first playoff game.
Marshall (6-foot-5, 232 pounds) has 970 career receptions for 12,351 yards and 83 touchdown catches. And his six seasons of 100-plus receptions is the most in NFL history. But his production has dropped off drastically the past two years.
Marshall had just 11 receptions for 136 yards and one touchdown in seven games played with Seattle. Last season he had just 18 catches for 154 yards and zero touchdowns in five games with the Giants before landing on injured reserve with an ankle injury.
The Saints obviously don't need Marshall to make a major impact for their offense since they have won eight straight games and are leading the NFL with 36.7 points per game. But they are very thin on experience at the receiver position after placing Ted Ginn Jr., Cameron Meredith and Bryant on injured reserve over the past month.
Michael Thomas is tied for the NFL lead with 78 catches. He is the only Saints receiver with more than 12 catches this season.
Marshall could come in handy in the red zone and on third downs -- a role Bryant was expected to play before he hurt his Achilles just two days after agreeing to a one-year deal with the Saints.
Marshall, a 2006 fourth-round draft pick by the Denver Broncos, also played with the Miami Dolphins, Chicago Bears and New York Jets. His last standout season came with the Jets in 2015, when he caught 109 passes for 1,502 yards and 14 TDs.