ALAMEDA, Calif. — The Oakland Raiders will be without star left tackle Donald Penn for their playoff opener against Houston.

The Raiders said Friday that Penn would be inactive after injuring his left knee in the regular-season finale against Denver.

That will be a big loss for a team already going into the game with a third-string quarterback at the helm. Rookie Connor Cook will be the first quarterback ever to make his starting debut in a playoff game with starter Derek Carr out with a broken leg and backup Matt McGloin limited by a left shoulder injury.

Penn allowed just one sack all season protecting Carr's blind side, according to Pro Football Focus. But that sack was costly as it led to Carr's broken leg on Dec. 24 against Indianapolis. Penn is one of the most durable players in the league with his streak of 160 consecutive regular-season games played tied with Cleveland's Joe Thomas for the longest active streak for an NFL offensive lineman.

"I did everything I could 2 play tomorrow I mean everything in tears right now haven't missed a game my entire career lost 4 words," Penn said on his Twitter account.

With Penn sidelined, the Raiders will likely move right tackle Menelik Watson to the left side and put Austin Howard in at right tackle, where he played much of the year when Watson was hurt.

"The coaches have plans," Howard said Thursday. "We'll see what happens. They make sure that we're all prepared. Fortunately, I feel that we have a lot of depth on this O-line. We have guys that can and want to play, so we'll get it taken care of."

The Raiders struggled to run the ball in the first meeting against the Texans with just 30 yards on 20 carries in a 27-20 win in Mexico City on Nov. 21. But the pass blocking was outstanding with Houston getting pressure on Carr just three times all game, according to Sportradar, matching a season low for the Texans.

Safety Nate Allen will also miss Saturday's game for the Raiders (12-4) at Houston (9-7) with a concussion. Allen had been playing in place of rookie Karl Joseph, who is questionable with a toe injury but said this week he plans to play.

Oakland is expected to get a boost on the defensive line with the return of tackle Stacy McGee, who missed the past five games with ankle and groin injuries.

Receivers Amari Cooper (shoulder), Michael Crabtree (ankle) and Andre Holmes (shoulder) and All-Pro guard Kelechi Osemele (ankle) and linebacker Malcolm Smith (hamstring) are all questionable but expected to play.

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