CHARLOTTE – Linebacker Luke Kuechly will miss the first game of his NFL career when the Panthers host the Houston Texans on Sunday.

Kuechly, who suffered a concussion late in Carolina's season opener against the Jacksonville Jaguars, was listed as doubtful on Friday's injury report but was downgraded to out Saturday. He spent the entire week in the NFL's concussion protocol and did not practice.

A.J. Klein will fill his middle linebacker spot just like he did in the second half of the opener, when Carolina's defense responded by shutting Jacksonville out to secure a 20-9 victory. Head coach Ron Rivera indicated Friday that if Kuechly is inactive, rookie linebacker David Mayo would be active.

Defensive tackle Star Lotulelei, who missed the season opener while recovering from a stress reaction in his foot, is listed as questionable. He returned to practice Wednesday for the first time in six weeks but had limited participation all week.

"We'll see. He had a really good day, though," Rivera said Friday.

Tight end Richie Brockel is also listed as questionable after returning to practice on a limited basis Friday. He sat out the final two preseason games and the regular season opener with a shoulder injury. Defensive end Wes Horton was limited in practice all week and is also questionable.