It didn't take a conversation with teammates or coaches. He didn't need anyone else to tell him.
It was late in the third quarter of Sunday's 25-3 loss to the Indianapolis Colts. Keenum took the snap from the Houston 7-yard line, caught it at about the 3, dropped back and held onto the ball as Texans left tackle Duane Brown blocked one of the best pass-rushers in the NFL. Brown blocked the ferocious Colts outside linebacker Robert Mathis for three full seconds -- an accomplishment against a player of that caliber.
"I went through my reads down the field and didn't see anybody open," Keenum said.
So he did something he knew was wrong almost immediately after he did it. He ran to his left.
"You have to step up in the pocket," Keenum said. "You can't just try to escape out this way. It's up towards the line. And that was another bad decision on my part. That one was totally on me."
The result was a complete disaster.
Mathis barreled toward Keenun. He hit him on the fourth second after the snap, popped the ball out into the end zone, and notched a franchise record 16.5 sacks this season. Mathis has the most strip sacks in NFL history. Brown landed on the ball to limit the damage to a safety. They were the final two points scored in the game.
"We have to be in sync," Brown said. "We were out of sync on that play. It was supposed to be a quick throw and it didn’t come out as quickly as it should have. I gotta hold my block longer. We just have to be in sync."
It was an afternoon filled with plays like that one. None so disastrous as a sack-fumble and a safety, but repeatedly Keenum made the wrong decision in the heat of the moment, even though he knew the right one.
"I was bad today," Keenum said, softly delivering a dejected news conference. "My teammates deserve better and my coaches deserve better. There is stuff that they tell me during the week multiple times and something goes in the game and I just make the wrong decision.
"... If someone knew the answer, I would like them to tell me."
Sunday's game in Indianapolis marked Keenum's lowest passer rating of the season at 42.3. He completed just 18 of 34 passes for 168 yards throwing no touchdowns and two interceptions. He nearly threw a third that would have been returned for a touchdown had Colts cornerback Darius Butler not dropped it.
Without knowing what he's doing wrong, Keenum would have little hope of fixing it.
That he understands it is a good sign and a direct result of his tireless preparation. He's not shirking his studies at all. But that's not changing what happens on the field each week.
Perhaps it's a matter of getting himself into the right habits and undoing the bad habits that came with the success he had despite them in a college system that didn't require such complicated understanding.
Or maybe it's all too much too soon.
"He's going though a process," receiver Andre Johnson said. "He can't take all the blame. We've all played a part in it. I had two drops today."
Maybe Keenum needs more time and will figure it out eventually. There is no set clock for a quarterback's development. But what's becoming more and more clear is the Texans can't go into next season expecting him to be the starter. They absolutely have to have another option.
The Texans can't win with Keenum playing as he is. And nobody is exactly sure what will change that.