I’d say this qualifies as big news on the eve of the Texans-Raiders playoff game:
For his part, Penn is as crushed as you’d expect.
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— Donald Penn (@DPENN70) January 6, 2017
That means the Raiders will likely be protecting the blind side of a rookie QB making his first professional start with their usual starting right tackle. From McDonald’s story linked above:
With Penn out, the Raiders are expected to move right tackle Menelik Watson to left tackle, with Austin Howard starting on the right side. Other options include moving Kelechi Osemele from left guard to left tackle and playing either Jon Feliciano or Vadal Alexander inside at left guard.