Comparing Brock Purdy, Trey Lance and Sam Darnold

Posted By on July 3, 2023

 

Brock Purdy. Trey Lance. Sam Darnold. Choose your fighter.

The main three combatants in the 49ers quarterback competition have drawn a wide range of reactions from fans this offseason.

San Francisco head coach Kyle Shanahan put the situation into perspective on the first day of OTAs.

“We have two guys (Trey Lance and Sam Darnold) who are talented enough to be taken in the top five of the draft and we have another guy (Brock Purdy) who played like it last year,” said Shanahan.

Let’s look at their passing numbers, specifically their on-target throw percentage from last year. Due to the lack of attempts for Trey Lance, I have combined his totals from 2021 and 2022.

Pro Football Focus (PFF) does a good job of breaking down incompletions due to the quarterback being hit while throwing (HAT), passes batted down at the line of scrimmage (BAT), and passes which were thrown away (TA). The PFF stats also include the number of drops for each quarterback.

To come up with the on-target throw percentage for each quarterback I have removed the hit as thrown, batted down passes and throw aways from each quarterback’s total attempts. I have also added the dropped passes into each quarterback’s completion totals.

Here are how the numbers stack up:

Brock Purdy: 155-233, BAT: 7, HAT:3, TA:11, Drops: 9

On target throws: 164-212, 77.4%

Notes: As you can see, Purdy was very accurate during his rookie season. He attempted passes in ten games, seven of those coming against playoff teams.

Trey Lance: 56-102, BAT: 5, HAT:3, TA: 3, Drops: 7

On target throws: 63-91, 69.2%

Notes: One of Lance’s four starts took place in rainy conditions in Chicago. If we take those throws out, it increases his on-target throw percentage to 71.2%.

He was also limited to only one and a half games with George Kittle and has yet to play with Christian McCaffrey. However, he did have Deebo Samuel available and the two connected for three of Lance’s five career touchdown passes.

Sam Darnold: 82-140, BAT: 2, HAT: 1, TA: 19, Drops: 1

On target throws: 83-118: 70.3%

Notes: Darnold had a far less talented offensive roster to work with in Carolina last year than what Purdy was working with in San Francisco. Still, he has quite a bit of ground to make up.

This article has 16 Comments

    1. OC,

      Yes, Here they are:

      Trey Lance, 3 interceptions. 5 turnover worthy throws on 121 dropbacks.
      Brock Purdy, 4 interceptions. 7 turnover worthy throws on 259 dropbacks.
      Sam Darnold, 3 interceptions. 3 turnover worthy throws on 162 dropbacks.

  4. Nice drop, Jack.
    Also, average length of pass completions.
    I believe that the chances of completing shorter throws (inside 20 yrds) would have a much better success ratio than passes beyond yrds.

    There is so much minutia involved in the QB position that all the stats can’t cover it all.
    That’s what makes the NFL so interesting.
    TC, can’t come soon enough!

  5. Several things stand out to me. First is that Darnold had only 1 drop which was much lower than Lance and Purdy. Did Darold make throws that were easier to catch or do Niners receivers just have the dropsies.
    The other thing that stands out is that Darnold had 19 throw always. That could be a quarterback issue but more likely it has to do with receivers not getting open but it seems like a huge number.

  6. Throw aways can be a good sign or a bad sign. It could mean a QB is not seeing or anticipating open receivers. Another way of looking at it could be the case of Jimmy G in 22, one of JGs biggest problems was forcing passes that end up being INTs. In 22 he finally learned to throw the ball away when there was no one open and his INT rate went way down. So I guess you could look at it two different ways. As to your first point, drops. If my memory serves me correctly the 9ers do have a higher than average drop rate.

  7. Lance was dealing with a finger injury for two of those starts.

    Furthermore, consider his severe lack of experience.

    He might be a top-5 QB, or even better, given a year or two of experience.

    Or, he may never be even average.

    Due to injuries, he’s never had an opportunity to either develop or show what he can do.

    I like Purdy. A lot.

    But, Lance has a higher potential ceiling.

    On the other hand, the 49ers may be basing every decision on what gives them the best chance to win a SB, this season.

  9. Having our traditional family BBQ, and starting it by listening to the great Ray Charles version of “America the Beautiful.”
    Enjoy your 4th of July, everyone! And be safe.

  11. Wow. This is a fantastic breakdown. Great work, Jack. I don’t really have stats to back it up but it felt like Purdy benefitted from quite a few plays where receivers made good plays on less than accurate passes. I specifically remember a play where Purdy threw a pass about 20 yards downfield on the left sideline that was very short and should have been intercepted but the Safety misplayed the ball so the WR was able to make an adjustment and catch the ball. Felt like Purdy just had breaks going his way that you really can’t count on consistently. I think PFF does a stat that covers “On Target Passes.” Do those stats line up with what you found for each QBs accuracy?

  13. Seems to be Brock Purdy has all the intangibles. He’s accurate, he can make throws in tight windows. He can loft a pass with touch. He can throw deep. He actually threw more (and connected) on more deep passes in what..8 game than Jimmy did in 2 years.

    He did all of this in his rookie year. I keep hearing all this talk of his “ceiling”. Not comparing the two, but Joe Montana supposedly didn’t have arm strength for the deep ball. I think the ceiling is the ability to take what the defense gives you, and Purdy in a few starts has demonstrated he is more capable than anyone else on the roster.

    My only hang up is, Jimmy played great in his first 5 games and didn’t look so great in the beginning of his 2nd year up until he got hurt. So… I’m anxious to see if Purdy will not only continue to play at a high level, but that he’ll actually get better.

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