Purdy has already missed two games this season. He played in Sunday's loss to the Jacksonville Jaguars but left the game with soreness in the same toe, keeping him out of Tuesday's practice—the only one of the short week.
If Purdy can't suit up, Jones will make his third start of the season. The former first-round pick has impressed in relief duty, and the 49ers are confident he can lead the offense in this critical NFC West matchup.
General manager John Lynch told NBC Sports Bay Area why the 49ers were aggressive in signing Jones during the offseason.
"Because we wanted to upgrade at the backup quarterback position," Lynch said. "It's so critical when you need him. And we've always liked Mac. We liked him a lot in the draft year (2021) that we studied him. We thought he was a perfect fit for what we did."
In his two starts this season, Jones has completed 66.3% of his 80 pass attempts for 563 yards, throwing four touchdowns and one interception. By comparison, Purdy has completed 65.8% of his 73 attempts for 586 yards in two games—but has four interceptions alongside four touchdowns.
Jones joined the 49ers with 49 career starts, giving the team confidence in his ability to step in and manage the offense effectively if needed. He's proven himself capable of doing that through two starts this season.
"It's been a real treat to watch him work, and kind of gained some confidence back," Lynch continued, "and play with some swagger that we saw him do at Alabama, and early in his career at New England. He really is playing with confidence and swagger, and it's been fun to watch.
"Mac's really capable of running this system at a high level, and he's been really good."
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