Spruill was helped off the field by two members of the medical staff.
The fifth-round draft pick from Syracuse was working as a reserve inside linebacker. He was part of a draft-day trade.
Spruill, known for his speed, was asked to put on weight upon arriving to the team.
The injury leaves the Falcons further depleted at inside linebacker. They already lost veteran Sean Weatherspoon to a season-ending Achilles injury. Newcomer Pat Angerer is going through the concussion protocol.
Paul Worrilow and Joplo Bartu have been working as starting inside linebackers when the Falcons work in their 3-4 scheme. The team also has high expectations for rookie Prince Shembo, a fourth-round pick from Notre Dame.
Veteran Nick Barnett, who worked out for the Falcons, could be an option at this point.