Kyle Shanahan is a perfectionist. Everyone knows it. If a wide receiver is two inches off his route depth, Shanahan notices. If a guard misses a pull block by half a second, it’s on the film. But for years, the one thing he couldn't quite "fix" through sheer coaching will was the depth behind his starting signal-caller. We've seen the seasons go up in smoke because of a broken foot or a torn ligament. It’s the San Francisco nightmare.
That’s why the recent San Francisco 49ers quarterback signing of Mac Jones—and the subsequent moves to shore up the room with Adrian Martinez—represents a massive shift in how this front office operates. It isn’t just about having a "guy" anymore. It’s about having a system-literate insurance policy.
Honestly, the Mac Jones addition was a stroke of genius that most people panned at first. "He’s a bust," they said. "The Patriots ruined him," others claimed. But look at the results from this 2025-2026 stretch. When Brock Purdy went down with that nasty turf toe injury early in the season, the season didn't crater. Jones stepped in, won five of his eight starts, and kept the Niners in the hunt for the NFC West. He averaged 268 yards per game. He looked... comfortable.
Why the 49ers Quarterback Signing Strategy Changed
For a long time, the Niners relied on high-upside projects or aging vets. Think Trey Lance. Think Josh Johnson. But after the 2022 NFC Championship debacle where they literally ran out of healthy arms, John Lynch and Kyle Shanahan clearly decided: Never again.
The San Francisco 49ers quarterback signing of Mac Jones in the 2025 offseason was the first domino. Jones is a traditional pocket passer, much like the "Kirk Cousins" archetype Shanahan has always coveted. He doesn't need to be Patrick Mahomes; he just needs to be an efficient distributor. By the time Purdy returned in Week 11, the team was 7-4. That doesn't happen with a random journeyman.
Then you have the Adrian Martinez saga. This is the stuff of football nerds' dreams. Martinez, the UFL MVP who lit it up for the Birmingham Stallions, was brought in specifically because he offers something Jones doesn't: mobility.
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The 49ers actually signed, released, and re-signed Martinez multiple times this season. It's like a roster-management dance. On November 17, 2025, Ian Rapoport confirmed he was headed back to the practice squad for the stretch run. Why? Because the Niners needed someone to emulate mobile threats like Seattle's Jalen Milroe on the scout team. It’s a specialized signing. He’s the "Swiss Army Knife" of the practice squad, and if disaster strikes again, he's a dynamic option off the bench.
The Elephant in the Room: The $265 Million Extension
We can't talk about the backup situation without acknowledging the king of the mountain. In May 2025, the 49ers finally did it. They gave Brock Purdy a five-year, $265 million extension.
That is roughly $53 million a year.
It's a staggering number for a guy who was once the very last pick in the draft. $165 million is guaranteed over the first three years. Basically, the Niners have tied their entire championship window to Purdy's right arm. Some critics, like Grant Cohn, argued the team "negotiated against themselves" by paying him after a statistically "down" year by his standards.
But if you’re John Lynch, what’s the alternative? Let him walk? Start over? In the modern NFL, if you have a guy who can win four playoff games in his first three years, you pay him. Period.
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The San Francisco 49ers quarterback signing of this massive extension changes the math for everyone else. It means the team has to be cheaper at other spots, which makes finding "reclamation projects" like Mac Jones even more vital. You can't pay a backup $10 million when your starter is making $50 million. You have to find the guys who are hungry for a second chance.
The Current Depth Chart (As of January 2026)
Heading into the Divisional Round matchup against the Seattle Seahawks, here is how the room actually looks. It's surprisingly deep for a team that usually has the worst injury luck in the league.
- QB1: Brock Purdy. The franchise. He's back from the toe and shoulder issues and looks like the 2023 version of himself.
- QB2: Mac Jones. The "Super Sub." He has the confidence of the locker room after keeping the ship afloat for two months.
- QB3: Adrian Martinez. The developmental/scout team ace. He's currently on the practice squad but is the designated emergency call-up.
- The Future: Kurtis Rourke. The seventh-round rookie out of Indiana. He’s been on the Non-Football Injury (NFI) list all year with a torn ACL from college, but the coaching staff is reportedly high on his traits for 2026.
Wait, what about Nate Sudfeld? Yeah, that was a weird one. He was signed in August 2025, waived three days later, re-signed, and eventually released again. It’s a reminder that being the third quarterback in Santa Clara is the most unstable job in sports.
What Most Fans Get Wrong About These Moves
People think a backup quarterback is just there to hold a clipboard. In Shanahan's offense, that’s just not true. The backup has to process information at the same speed as the starter because the play-calling doesn't change.
When Jones was signed, people expected the playbook to shrink. It didn't. He was hitting Jauan Jennings and Ricky Pearsall on the same timing routes Purdy uses. This is why the San Francisco 49ers quarterback signing philosophy is so specific now. They aren't looking for the most talented arm; they are looking for the fastest brain.
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The team even brought in guys like Carter Bradley (Gus Bradley's son) and Tanner Mordecai during the 2025 camp. Neither stuck. Why? Because they couldn't handle the "verbal gymnastics" of the play calls. Shanahan’s plays are famously long—sometimes 15 words just to describe the formation and protection. If you can't spit that out in the huddle, you're gone.
Actionable Insights for the 49ers' Postseason
If you’re watching the 49ers in the 2026 playoffs, keep an eye on how they use their roster spots. With the new NFL rules regarding the "Emergency Third Quarterback," Martinez can suit up without taking an active roster spot on game day, provided he's on the 53-man list.
Here is what really matters for the upcoming weeks:
- Watch the Practice Squad Elevations: If the Niners elevate Martinez on a Saturday, it usually means Purdy or Jones is dealing with a "hush-hush" minor tweak.
- The Mac Jones Factor: Don't be surprised if you see a "Mac Package" in short-yardage or specific red-zone looks. Shanahan has experimented with using his backup's different throwing angles to confuse defenses.
- Salary Cap Management: Purdy's cap hit is about to explode in 2026 ($24.7 million). This means the 49ers will likely look to trade Mac Jones this coming offseason to a team like the Colts or Giants to recoup a draft pick, moving Martinez or Rourke into the primary backup role.
The days of the 49ers' season ending because of a single hit to the quarterback are over. They’ve built a room that is resilient, smart, and—dare I say—expensive. But in a league where Sam Darnold is currently leading the Seahawks to division titles, having three guys who can actually play isn't a luxury. It’s a necessity.
To stay ahead of the next roster move, monitor the Tuesday transaction wire for any "Reserve/Future" contract signings involving former college starters. This is where the 49ers typically find their next "diamond in the rough" to compete with Rourke and Martinez during the 2026 OTAs.