Kyle Shanahan had a contingency plan in place if the San Francisco 49ers defeated the Philadelphia Eagles to advance to Super Bowl 57.

Shanahan revealed to reporters Thursday that the 49ers would have signed eight-time Pro Bowler and current St. Michael Catholic (Alabama) High School football coach Philip Rivers had the 49ers defeated the Eagles in last season’s NFC championship game.

“Yeah,” Shanahan answered when asked if he was serious about signing Rivers last postseason. “He was prepared to. Now that’s stuff we talked about throughout the whole year. We would've had to seen how that was for the Super Bowl, but that was the plan most of the year.”

The 49ers went through a merry-go-round of quarterbacks and finished last season with no healthy QBs. Trey Lance suffered a season-ending ankle injury in Week 2, Jimmy Garoppolo sustained a season-ending foot injury in Week 13, Brock Purdy injured his elbow in the NFC championship game and Josh Johnson was concussed in the conference championship tilt.

After being snake bitten at the position, it’s hard to question Shanahan about his possible emergency plan. Afterall, the 49ers were in dire straits at quarterback.

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It would’ve been fascinating to see Rivers come out of retirement and suit up in Super Bowl 57. The long-time QB last played an NFL game on Jan. 9, 2021, and announced his retirement on Jan. 20, 2021.

Rivers never made it past the conference championship in his superb 17-year career, but he wouldn’t have been lacking in experience.

Rivers produced 63,440 yards, 421 touchdowns and 209 interceptions in 244 career regular-season games. He played 16 seasons with the Chargers and one year with the Colts. He holds Chargers' all-time records in career passing yards (59,271) and touchdown passes (397).

Follow USA TODAY Sports' Tyler Dragon on Twitter @TheTylerDragon.