Bryant was helped off of the field after apparently suffering the tear on the last play at practice, reports ESPN's Adam Schefter.
Bryant signed a prorated contract that will pay him $600,000.
Dez Bryant's worst fears are now a reality.
The person spoke to The Associated Press on condition of anonymity because the team has not announced any details of Bryant's medical exam.More news: Vettel smashes Interlagos lap record
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A number of Saints players sent their support to Bryant on Twitter on Friday. The three-time Pro Bowler was released in April when he was due to earn $12.5 million.
The recovery timeline puts Bryant on track to potentially be ready for training camp next year, when he again will be a free agent.
A serious injury to Bryant, 30, could lead to the Saints taking a second look at veteran Brandon Marshall, who also worked out for the team this week. But news broke earlier this week that Dez agreed to a one-year contract with the New Orleans Saints.
Bryant said he had turned down other opportunities to work out this season, without offering any specifics.
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.