Lions head coach Dan Campbell said Monday that Barnes (knee) will miss "a significant amount of time," Tim Twentyman of the Lions' official site reports.
Barnes was carted off during the second quarter of Sunday's 20-13 win over the Cardinals with a knee injury. Though Campbell didn't go into details regarding the nature of Barnes' knee injury while the Lions await a second opinion, the 25-year-old linebacker is expected to be placed on injured reserve, per Nolan Bianchi of The Detroit News. Barnes recorded 10 tackles and one pass breakup through the Lions' first three games.