Wilcox is scheduled to get a second opinion on his right knee to determine the severity. The Falcons won't address the injury until coach Dan Quinn meets with the media following Tuesday's practice.
Following Monday's practice, Quinn did not address the injuries suffered by both Wilcox and reserve defensive lineman Michael Bennett, who appeared to injure his right ankle while being blocked by rookie first-round right guard Chris Lindstrom. Two members of the athletic performance staff helped Bennett off the field.
Wilcox remained on the ground kneeling on his left knee after a play and didn't immediately get up when defensive backs Isaiah Oliver and Damontae Kazee came over to check on him. Both Kazee and strong safety Keanu Neal helped Wilcox off the field a little more than an hour into practice.
The 28-year-old veteran Wilcox was an important offseason signing as the Falcons searched for quality depth behind Neal and starting free safety Ricardo Allen. Neal had a season-ending ACL tear in 2018, and Allen had a season-ending Achilles tear. Both practiced in 11-on-11 drills Monday, but their team reps were limited.
Wilcox impressed coaches during the offseason with his ability to play both safety spots. The Falcons even showed a package Monday with Neal, Allen and Wilcox all on the field together.
Without Wilcox, the Falcons might turn to Chris Cooper and Sharrod Neasman to provide depth at the position. There's always the possibility of signing another free-agent safety, and Kazee, who is playing nickel corner now, thrived as Allen's replacement at free safety last season.
The Falcons don't want to have a repeat of last year in terms of injuries. They saw six starters -- Devonta Freeman, Andy Levitre, Brandon Fusco, Deion Jones, Allen and Neal -- go on injured reserve, with Jones the only one to return to the lineup before season's end.
The NFL Network was first to report Wilcox's ACL injury.