Earlier this week, Kirk Ferentz ignited a firestorm when he suggested Iowa fans “smelled a rat” when they booed Penn State defensive injuries in the Hawkeyes’ 23-20 win over the then-No. 4 Nittany Lions.

Perhaps next week he could encourage Hawkeyes fans to direct their boos in the proper direction: at his own son’s sorry offensive play-calling. Iowa’s Achilles heel was on full display in a 24-7 loss to Purdue that finally demonstrated how unrealistic talk of the Hawks as a CFP contender was.

No sequence better demonstrated offensive coordinator Brian Ferentz’s Cro-Magnon playbook than the one that officially squelched Iowa’s hopes of an undefeated run to the Big Ten Championship Game.

Granted a last gasp at life thanks to Ivory Kelly-Martin’s 67-yard kickoff return into Purdue’s red zone, Young Ferentz did not seem to recognize he had 12 minutes to close a 17-point deficit. Or that his offense had at that point produced 6 yards in the second half.

With the clock ticking, Ferentz dialed up a quarterback sneak on a long third-and-2 against a defensive front that had been whipping Iowa’s butt all day. When he didn’t get it, he tried it again. And failed again.

It’s not as if Purdue is the only defense that has done this, either. It’s habitual. Iowa came into the game dead-last in the Big Ten with 48 tackles for loss allowed. Yet Brian and Kirk Ferentz looked at their offensive line and said: “Yeah, let’s trust those guys for our last gasp.”

The whole sequence was a microcosm of why Iowa is not ready to swim in the deep end: this offense has neither the horses nor the jockey.

The Hawkeyes’ rise to No. 2 in the country required perfection on defense and special teams. And when it got something less than perfection from those two phases — for the first time all year, Iowa didn’t get an interception — the offense was unable to carry its own weight.

This weakness was no mystery. Iowa came into the game last in the Big Ten in yards per play and 13th in yards per carry. The Hawkeyes were 12th on third-down conversions. They won’t improve in any of those areas after getting the business from the Boilers.

Despite those woeful numbers, few would have pegged Purdue as the team to expose Iowa. (Though given that this is the 9th time an unranked Purdue team has beaten a Top-2 opponent, perhaps we should have.)

True title contenders almost always have to win a game where they can’t rely on their tried-and-true formula. With Purdue’s offense doing an excellent job of minimizing mistakes and exploiting the gaping absence of star cornerback Riley Moss with receiver David Bell, this was that game for Iowa.

With 4 turnovers, 6.1 yards per pass attempt and 2.5 yards per rush, Ferentz’s offense fell woefully short.

Heading into a bye week, Iowa needs to recalibrate. If the takeaways stop coming in bunches, this team goes from one of the most dangerous in the country to one that looks capable of being surpassed by Minnesota within its own division.

Considering that Purdue still has games against Michigan State and Ohio State, Iowa likely remains in the B1G West driver’s seat. But the Hawks have yet to prove they have enough offense to drive to Indianapolis.

This is unlikely to be the last time this season Iowa’s defense is unable to carry the team on its back. The question is whether the offense will ever be able to pick up the slack.