Slay injured his back in Monday's wild-card game against Tampa Bay and was carted off the field, Ralph Vacchiano of Fox Sports reports.
The injury occurred while Slay attempted to make a tackle in the fourth quarter. He grabbed at his back and remained down for some time before being carted to the locker room. Slay had just come back from a different injury -- he missed the Eagles' final four games of the regular season due to a knee issue.