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The 49ers turned to Jimmy Garoppolo early this season after initial starter Trey Lance suffered a season-ending ankle injury. Now, they're turning to rookie Brock Purdy after Garoppolo suffered his own season-ending injury in Week 13 against the Dolphins. After taking a sack on San Francisco's first drive of Sunday's win, Garoppolo was seen favoring his lower body on the sidelines, then visited the medical tent before being carted to the locker room. Purdy replaced him for the remainder of the game.

Coach Kyle Shanahan announced immediately following the game that Garoppolo suffered a broken foot and will require surgery that will sideline him for the remainder of 2022. Garoppolo had been enjoying one of the most productive seasons of his 49ers career, filling in for Lance while guiding the 49ers atop the NFC West. His own injury history, however, was reportedly one of the primary reasons San Francisco sought Lance as a potential long-term starter. Now, it's suddenly back in the spotlight.

The 49ers quickly made a move Sunday night, signing veteran Josh Johnson off the Broncos' practice squad, according to ESPN. Johnson appeared in four games last year with the Jets and the Ravens. The 49ers also have Jacob Eason on their practice squad and he would appear to be up next as Purdy's backup.

Purdy, who was taken with the final pick of the 2022 NFL Draft out of Iowa State, was the only other active QB on the 49ers roster when he took over Sunday. Lance is on injured reserve, and previous backup Nate Sudfeld was released as part of final roster cuts over the summer. Purdy took over with the 49ers trailing 7-3 but led San Francisco to a touchdown drive on his first possession, and finished 25 of 37 for 210 yards, two touchdowns and one interception in the team's 33-17 win.

This isn't the first time Garoppolo's had a season prematurely ended due to injury. He previously missed most of the 2018 and 2020 seasons due to an ACL tear and high-ankle sprain, respectively.

CBS Sports stats guru Stephen Oh ran the numbers, and here's how the 49ers' prospects change with Purdy at quarterback. As Oh pointed out, the dropoff is meaningful but not nearly what you would expect when your starting QB is replaced by "Mr. Irrelevant" due to the 49ers having such a strong team otherwise.

49ersWinsWin %DivisionPlayoffsConferenceChampionship
w/ Jimmy Garoppolo11.366.5%73.4%99.1%21.7%10.8%
w/ Brock Purdy11.064.7%68.7%98.5%17.8%8.1%