An MRI exam confirmed that Bryant tore his Achilles on Friday during his second practice with the team, ESPN reported Saturday afternoon.
The injury occurred two days after Bryant signed a one-year contract with New Orleans as a free agent. Bryant was hurt on the final play of Friday's practice, according to ESPN.
"(He) just went down," a Saints source said Friday. "Freak deal. No contact."
Bryant, who was released by the Dallas Cowboys in mid-April, posted a message on his Twitter account Friday before the injury was confirmed.
"Things was just starting to heat up for me," wrote Bryant. "I won't question the man upstairs... this is the ultimate test.. thank you everyone for the prayers."
The 30-year-old Bryant was hoping to resurrect his career with the Saints and was looking forward to teaming up with quarterback Drew Brees. Even if he was healthy, the Saints were not expected to play him Sunday against the Cincinnati Bengals.
The 6-foot-2, 220-pound Bryant was released by the Cowboys in a cost-cutting move.
Bryant's on-field productivity slipped in 2016 and 2017. The once-dominant physical receiver has not surpassed 900 receiving yards in a season since signing a lucrative contract extension in 2015 after being named first-team All-Pro in the previous season.
Bryant caught 88 passes for 1,320 yards and a career-high 16 touchdowns in 2014, the third straight year he surpassed 1,200 yards. From 2012-14, he caught 273 passes for 3,935 yards and 41 touchdowns.
For his career, Bryant has 531 catches for 7,459 yards and 73 touchdowns in eight seasons, all with Dallas.
Bryant's last game with the Cowboys was the 2017 regular-season finale on Dec. 31, when he caught three passes for 24 yards.