Rapoport adds the injury could jeopardize the start of training camp for Pierce next week. However, he should be ready for the start of the regular season.
Pierce signed a major deal with the Vikings in free agency last year but ended up opting out of the 2020 season due to COVID-19 and his asthma.
He signed a three-year, $27 million deal which was tolled to effectively start in 2021.
Pierce, 28, wound up signing on with the Ravens as an undrafted free agent out of Samford in 2016. He played out the final year of his three-year rookie contract before returning to the Ravens on a second-round restricted tender.
He was testing the open market as an unrestricted free agent for the first time in his career when he signed a three-year, $27 million deal with the Vikings in 2020.
Pierce was slated to make a $3 million, fully-guaranteed base salary in 2020 before opting out due to the pandemic. That total was tolled to 2021.
In 2019, Pierce appeared in 14 games and recorded 35 total tackles, two tackles for loss, 0.5 of a sack, and one fumble recovery. Pro Football Focus rated him as the No. 46 interior defender out of 119 qualifying players.