Notre Dame will have to replace quarterback Ian Book, who started 34 of the last 35 games for the Irish. Book's likely replacement will be former Wisconsin signal caller Jack Coan. The former Badger missed the 2020 season after leading Wisconsin to the Big Ten title game and the Rose Bowl during the 2019 season.
I wanted to break down the two quarterbacks and compare their production, their skillsets and show the differences that Coan will bring to the offense.
Let's begin by looking at Book's production from the 2020 season and Coan's production from the 2019 season, his last in the starting lineup. (all data from Pro Football Focus)
Book's production came in 12 games while Coan's came in 14 games. Notre Dame went 10-2 in Book's final season while Wisconsin went 10-4. Book and the Irish went 2-2 against ranked opponents while Wisconsin went 3-3 against ranked opponents.
Here are the comparisons between Book and Coan with the deep ball (throws that travel at least 20 yards past the line of scrimmage).
Coan completed the deep throws at a significantly higher rate than Book, had three more touchdowns on deep balls on nine fewer attempts, and had a significantly higher passer rating.
Here are the comparisons on intermediate attempts (throws that travel between 10-19 yards past the line of scrimmage).
Coan's completion rate on these throws was almost 10% higher than Book's, and his yards per completion and attempt were much higher, as was his passer rating.
Here's the comparison of all throws that traveled at least 10 yards past the line of scrimmage.
Book attempted far more throws than did Coan, but Coan was clearly more successful. His completion rate was almost 10% higher, his yards per completion rate was slightly higher and his yards per attempt was dramatically higher, as was his passer rating.
If you compare Book's 2019 numbers to Coan's they were a bit closer. Book completed 50.4% of his attempts beyond 10 yards, averaged 24.1 yards per completion and 12.2 yards per attempt. His passer rating was 186.22.
Not as good as Coan's, but certainly closer.
Book was better on throws between 1-9 yards past the line.
Coan also had better numbers under pressure.
Coan - 53.1%, 7.4 yards per attempt, 13.9 yards per completion, 4 TD, 2 INT
Book - 49.5%, 6.6 yards per attempt, 13.4 yards per completion, 5 TD, 1 INT
Where Book clearly separated himself from Coan was as a runner. Book rushed for 485 yards and nine touchdowns this past season, while Coan rushed for just 22 yards and four touchdowns in 2019. Part of that is how the system works, but Book is certainly a better athlete and runner than Coan.
Here's how I compare their skills:
ARM STRENGTH/DEEP BALL
There are two ways to evaluate arm strength and throwing the ball down the field. The first involves the ability to power the ball down the field. That is where I give Book the advantage.
One area where I tend to disagree with most analysis I see or hear about Book regards his arm strength. Book can make all the throws you need a quarterback to make, and he can power the ball downfield with more authority than Coan.
Where Coan is better as a deep ball thrower is he's a more confident deep ball passer, he throws with better timing and he throws with better accuracy on most deep throws. But Coan can't get the ball over top of defenses the way Book could, although Book rarely took advantage of that arm talent.
Accuracy involves more than just completion rate. The problem with just using completion rate is that it can in part be determined by the system. If an offense throws significantly more deep throws, or a higher volume of screens it will alter the overall completion rate.
The other aspect to accuracy is the ability to place the ball where you want it.
Book is a slightly more accurate deep ball thrower when he actually takes his shots, which is due partly to his advanced arm strength. The problem is Book was off-target and completed deep balls at a lower rate because his timing was much worse than Coan's, and that led to him being more off-target.
Coan is more accurate on moving deep throws, but he can be a bit more off-target on some of the deep throws that require more power.
Coan is the more accurate thrower on intermediate and short throws, and he often had to throw into much, much tighter windows than Book did due to Coan throwing to less effective and talented weapons.
This category contains things like read progression ability, timing as a passer, anticipation and the ability to manipulate the defense and handle the pocket.
Book gets the advantage when it comes to being able to escape the pocket and make plays with his legs, and its a significant advantage. Coan has advantages on the rest, including being better at reading pressures and getting the ball out quickly and accurately.
Where Coan has a significant advantage over Book the remainder of the categories. He is a consistently better decision maker while also running a complex offense from a reads standpoint. His timing is better, he anticipates much better (which means throwing receivers open more effectively), he's a much more aggressive passer (willingness to throw into tighter windows) and his ability to manipulate defenses with his eyes is far better than what we've seen from Book.
Both have their issues in the pocket, but Book created more pressures than did Coan. Far too often Book would either bail out of the pocket too soon, or he would escape outside when the protection was meant to push edge rushers outside, which meant he was running into the pressure. Coan's issue is he took more backside hits than did Book, which tells me at times he doesn't see wide backside rushers as well.
At the top of the article is a video of Irish Breakdown football analyst Vince DeDario and myself breaking down Coan's game. You can also listen to that analysis in podcast form below.
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