The Oakland Raiders will start their first playoff game since 2002 with a third-string quarterback and backup left tackle.
Penn suffered the injury late in the Week 17 loss to the Denver Broncos. He sat out all practice all week.
Saturday's absence will mark the first missed game for the 33-year-old in 10 seasons, since he took over the starting gig in Tampa Bay in 2007. Penn played in 160 consecutive games, per NFL Research. Penn has been one of the top left tackles in the NFL all season, particularly in run blocking.
The news is troubling for rookie Connor Cook, making his first career start. In relief last week, Cook showed a big arm and ability to get through his progression, traits he displayed during his career at Michigan State. However, Cook turned the ball over and for stretches looked every bit a lost rookie with few practice snaps under his belt.
Without his best blindside blocker against Jadeveon Clowney and Whitney Mercilus, Cook will be under siege. Menelik Watson is expected to start at left tackle with Austin Howard returning to the right side.
A heretofore fantastic offensive line is banged up at the worst possible time. Oakland allowed the fewest sacks (18) in the NFL this season. The Raiders ranked sixth in the NFL with 120.1 rush YPG and 11th in rush yards before contact (2.4) in 2016.
On the bright side, the Raiders defense could get Karl Joseph back. The safety was listed as questionable with a toe injury. Joseph's return would be a big boost for a secondary that's sagged without the playmaker.
Matt McGloin is listed as questionable and could backup Cook if he's healthy enough to be active.
Amare Cooper and Michael Crabtree were listed as questionable -- as they have been most of the latter part of the season -- but will play. Andre Holmes and Malcolm Smith were also listed as questionable to play.