One big difference between Sam Darnold, Brock Purdy may decide Seahawks-49ers

Purdy may have a better supporting cast around him in Santa Clara, but it's no contest when it comes to pure arm power.

Aug 25, 2023; Santa Clara, California, USA; San Francisco 49ers quarterback Brock Purdy (13) and quarterback Sam Darnold (14) during the game against the Los Angeles Chargers at Levi's Stadium. | Sergio Estrada-Imagn Images

After joining the Seattle Seahawks, Sam Darnold gave credit to Brock Purdy for helping him unlock the next level of his game before he had his breakout season with the Minnesota Vikings. Darnold effectively told reporters that observing Purdy in 2023 helped him realize he didn't need to force the action and could simply get the ball out on time to his playmakers and let them do the rest.

Now, Darnold will be facing Purdy and the San Francisco 49ers this evening with the NFC West championship and the No. 1 seed in the conference on the line. Darnold can also earn up to $2 million in incentives if he plays well enough.

While Darnold's performance has dropped off in the second half of the season and Purdy is red-hot coming into this matchup, there's one area where Purdy will never be able to challenge Darnold: unloading the long ball. 49ers on SI editor Grant Cohn broke down the stark difference between their deep ball stats this season.

Sam Darnold vs. Brock Purdy 15+ yards

Throws 15+ yards downfield.

Brock Purdy
0.33 EPA/play
64.8 passer rating
3 TDs
7 INTs

Sam Darnold
0.78 EPA/play
101.1 passer rating
10 TDs
6 INTs

— Grant Cohn (@grantcohn) January 2, 2026

A lot goes into these numbers to be fair, and Darnold has better vertical weapons than Purdy, including JSN, Rashid Shaheed and the unfortunately done-for-the-season rookie Tory Horton.

However, Darnold also had the best deep ball numbers in the league last year - and this particular stat has more to do with his long accuracy and superior arm talent than anything. Purdy does what he does well, but if you need a deep completion the choice between the two is an easy one.

When these teams met back in Week 1 they were both somewhat a mystery - as every team is coming into a new season. By now we know what both are all about, though, and that will play into Darnold's favor this week.

The Niners defense played Seattle brilliantly in the season opener, but they've since lost their two best players to injuries and rank 25th in passing defense going into Week 18. They're also dead last in the league in sacks and play a lot of cover 4, which should play into Darnold and JSN's hands.

When the odds dropped the Niners were considered 1.5-point favorites, but the line has since shifted in the opposite direction and the Seahawks are now favored by 2.5.

• Game odds refresh periodically and are subject to change. 
• If you or someone you know has a gambling problem and wants help, call 1-800-GAMBLER.

Dec 14, 2025; Seattle, Washington, USA; Seattle Seahawks quarterback Sam Darnold (14) exits the tunnel during player introductions before a game against the Los Angeles Chargers at Lumen Field. | Steven Bisig-Imagn Images

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