How unbelievably poor was the Oakland reserve QB? Couldn't even execute 5 yard passes. I am amazed that the backup can be so poor.
Edit: Sorry Tal wasn't a dig. Just thought the bloke was completely useless - not a regular NFL watcher and hadn't seen your post so not after timing!
No problem, Dung.
He didn't play well, which was always a possibility on debut under immense pressure, in a situation where the team wanted to give him this year to learn the system before using him as a backup next year.
But this was one of those occasions where an entire team just doesn't turn up. The Offensive line was weakened, then weakened further, but it all so played poorly, as the backups should have been able to cope better; they just let Houston run through or around them time after time. This meant Cook was always under attack and even Aaron Rodgers and Ben Roethlisberger will struggle when being attacked every snap.
Then there's the receivers. They've been dropping balls all season, but there were 50 yards left on the ground last night from catches you or I would expect to make. To quote Sir G of B,
"my Aunt Annie could have caught that in her pinny". That does nothing for a fledgling QB's confidence, let alone his stat lines.

The running game was abysmal, too, with Latavius Murray (who has had a mediocre season), being still worse. That means there was no way to control the clock and it left Cook needing to find throws against what might be the best secondary in the AFC. When the QB isn't getting the chance to plant his feet and take his time with his throws, the secondary is even more likely to intercept.
Then there was the playcalling. In the first half, they were simply far too conservative; too many screen (sideways or very short) passes, which were made all the more difficult because he was often having to throw over or around an enveloping mass of navy blue. They didn't get him to throw down field anywhere near often enough. Again this made them very easy to defend against.
Cook lost some throws with poor foot placement and raw mechanics. He wasn't supposed to be there last night. He didn't play well, but, had the team that Derek Carr got to 12-3 been playing, his stat line would have been better. I don't think this changes his status for next season; he will be the backup next year. He made some excellent throws late on, when the Texans stopped blitzing and gave him time. A stronger offensive line would have given him the chance to do that earlier.
I'd also say Brock Osweiler had a much better than expected first half. Not $72m better, but better nonetheless. The Texans have good wide receivers, a solid tight end partnership and an excellent defense. They only need their quarterback to be competent to do well. That's what they got. Saves the head coach his job, too.
They'll still be double digits underdogs in Foxboro.
Cliffs: He wasn't what I was looking for, but Cook wasn't the problem last night. Carr would have struggled to put up 20 points with no protection, poor calling from the sidelines and butterfingered receivers.