For the second straight week, 49ers backup quarterback C.J. Beathard replaced the starter.
This time, Beathard relieved Jimmy Garoppolo after the 49ers trailed the Miami Dolphins 30-7 at halftime Sunday at Levi's Stadium. Garoppolo, making his first start since sustaining a high ankle sprain in Week 2, was pulled in order to avoid further injury risk.
"That is because I want to protect Jimmy," 49ers coach Kyle Shanahan told Fox Sports sideline reporter Lindsay Czarniak.
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Garoppolo completed just seven of his 17 pass attempts for 77 yards in the first half, throwing two interceptions and no touchdowns. He ended his day with a 15.7 passer rating, which the Associated Press' Josh Dubow found was the fourth-lowest by a 49ers starting QB since 1979.
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Garoppolo played perhaps his best half of the season in Week 2 against the New York Jets, completing 14 of 16 passes for 131 yards and two TDs. Nick Mullens played in place of Garoppolo in the second half after he sustained a high ankle sprain, and Sunday was Garoppolo's first appearance since then.
San Francisco 49ers
The 49ers went 1-1 in Mullens' two starts. He was dominant against the New York Giants in a Week 3 win, but Beathard replaced Mullens last week during the fourth quarter of the 49ers' 25-20 loss to the Philadelphia Eagles. Mullens had been ahead of Beathard on the 49ers' depth chart since replacing him in the 2018 season after Garoppolo sustained a torn ACL, but Shanahan told reporters last week that Beathard had supplanted Mullens on the depth chart.
Mullens was inactive Sunday.