Can Iowa's offense produce against Michigan? Saturday is an important test.

Iowa football coach Kirk Ferentz didn't mince words when describing the challenge for his offense in Saturday's game against No. 4 ranked Michigan.

The Wolverine defense is the nation's second-highest rated unit (just behind Iowa's), according to Pro Football Focus. Statistically, they're ranked seventh nationally in scoring defense (11 points per game) and eighth in total defense (244 yards per game).

"These guys look like an NFL defense," Ferentz said. "I mean, they're big, they're strong and they're athletic. Other than that, no problem. And a good scheme."

The good news: Iowa's offense (which is still ranked dead last nationally in total offense) has taken steps forward in the last two weeks. The Hawkeyes passed tests against Nevada, the 104th-ranked defense nationally, and Rutgers, which is the ninth-ranked defense just behind Michigan and Iowa (ranked No. 6). Rutgers is a legitimate Big Ten defense, but the challenge is different with Michigan's defensive unit of four and five-star talent.

Iowa's executed well enough over the last two weeks to net more positive results, but Ferentz knows it's going to take that and then some for another top five upset at Kinnick Stadium (11 a.m. CT on Fox).

"It's like an NFL playoff game," Ferentz said. "Each and every play something can happen. They're a big, strong, athletic team so if you're not on your game each and every play, big things can happen against you."

How many points will Iowa's offense need to give the team a fighting chance? Michigan holds the No. 2 scoring offense nationally at 50 points per game, but Iowa's defense will likely hold them far from that number. If recent history is any indication, somewhere around 20 to 25 points might suffice. Since the 2016 season, Iowa's defense has allowed 17.4 points per game which ranks 11th nationally. Per that average, Iowa holds a 49-6 record (89% winning percentage) when it scores 18 points or more, versus an 8-16 (33.3%) record when the point total is less than 18 points. 

Can Iowa get there against Michigan? We'll find out on Saturday. But, it seems like the offense is gaining confidence, and that's a result of better practice habits carrying over to games.

But another big jump is needed on Saturday.

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"It's a process," Ferentz said. "The more you get your guys healthy and the more guys involved, the better off it's going to be. But the most key and central element is practice. That's how we're going to gain ground is doing a good job during the week. We're a little bit younger on offense, and we don't have as much veteran leadership as we do on defense, so that's a bigger challenge. But the guys understand that (practice) ― that's where good things happen typically, and then you've got a chance to carry it to a game."

Iowa's offense ranks last nationally in first down offense and 122nd in third down conversions.

One of the biggest factors for Iowa's offense on Saturday is sustaining drives. Through four games, Iowa's averaging 4.8 plays per possession, overall the offense ranks 12th in the Big Ten in time of possession. It's critical that the Hawkeyes limit the number of Michigan possessions.

Within those drives, first down offense has been the biggest concern. The Hawkeyes rank last nationally in first down offense which leads to third and long situations, in which they rank 122nd in third down conversions (28%). Rutgers was a step in the right direction (six plays per possession) but Iowa ran into a problem with early down mistakes. Five of eight failed third-down conversions were preceded by negative plays: three penalties on first or second down, a first-down sack for minus-8 yards and another negative run on first down. The offense has struggled as is — self-inflicted mistakes against Michigan is a recipe for disaster.

"Negative plays really hurt a team's chance of advancing and scoring," Iowa quarterback Spencer Petras said. "I'm not sure the exact number, but statistically there's a huge contrast between drives with no negative plays and drives with negative plays in terms of if you're going to score. But at the end of the day, we still need to execute better on third down. We do have good answers and third and 15 is going to be tough, but the third-and-9's, we still have a good chance there if we just execute."

Petras has been considerably better in his last two starts, completing nearly 60% of his passes and playing turnover-free. Tight ends Sam LaPorta and Luke Lachey were a big part of the Rutgers win, accounting for 114 of the 148 total passing yards and might play an equally big role against Michigan. In last year's Big Ten championship game, two of Iowa's first three drives were 10 plays that went deep into Wolverine territory. The tight ends were the catalysts of those drives, combining for four 10-plus yard plays on those drives.

But Iowa's receivers only received two targets against Rutgers and must be a bigger factor on Saturday. Petras noted that even though they weren't featured much, film review showed that the unit that's been hampered by injuries continued to move better on the field.

Perhaps where the Hawkeye offense has seen the most growth recently is in the running game. Sophomores Gavin Williams and Leshon Williams and true freshman Kaleb Johnson have shown signs of becoming a formidable attack. Michigan is stout against the run but Iowa just had a strong showing against Rutgers, who entered that game with the No. 1 rush defense nationally.

With injuries again at wide receiver (no Keagan Johnson), Iowa might need to rely heavily on the run. 

"My guess is we're going to need all three (running backs)," Ferentz said. "All three of them are really quality players and all have different strengths and weaknesses, so I'm glad they're on our team."

In some ways each of the two games have been a test for Iowa's offense, but Saturday is a significant benchmark. The Hawkeyes have their sights set on consecutive Big Ten West titles. To do so, they have to show an ability to play on par with elite teams like Michigan.

It's going to take a three-phase effort but the offense in particular has to provide support. If they can, Saturday's game can be a tightly contested contest in the final minutes.

"We're certainly doing better than a month ago, certainly," Ferentz said. "Getting some other guys back helps you. It helps your tempo. But it's day-to-day.

"We're looking big picture, too, not just each day and not just each week. But it's a race against time."

Kennington Lloyd Smith III covers Iowa Hawkeyes football and men's basketball for the Des Moines Register. You can connect with Kennington on Twitter @SkinnyKenny_ or email him at ksmith@gannett.com.