Long before the San Francisco 49ers ran out of healthy quarterbacks in their NFC Championship Game loss to the Philadelphia Eagles, they had begun making contingency plans for the position had they advanced to Super Bowl LVII.

One of those plans involved bringing veteran signal-caller Philip Rivers out of retirement to take on the Kansas City Chiefs.

"He was prepared to," Niners coach Kyle Shanahan said Thursday. "Now that's stuff we talked about throughout the whole year. We would've had to have seen how that was for the Super Bowl, but that was the plan most of the year."

That possibility never materialized as the Niners lost starter Brock Purdy to a torn ulnar collateral ligament in his right elbow and backup Josh Johnson to a concussion. Purdy finished the game but was unable to throw, essentially eliminating any chance the 49ers had of advancing. Those injuries came after the Niners lost Trey Lance to a broken right ankle in Week 2 and veteran Jimmy Garoppolo to a broken left foot Dec. 4.

Had the Niners defeated the Eagles and signed Rivers, he would have been playing in the league for the first time since 2020. But joining the Niners in that hypothetical scenario would have given Rivers, 41, his first chance to play in a Super Bowl.

In 17 seasons as the quarterback of the Los Angeles Chargers and Indianapolis Colts, Rivers was an eight-time Pro Bowler and the NFL's Comeback Player of the Year in 2013. He ranks sixth all time in passing yards (63,440) and touchdowns (421) and 16th in passer rating (95.2).

Since retiring on Jan. 20, 2021, Rivers has served as the coach of the St. Michael Catholic High team in Fairhope, Alabama.

For his part, Rivers told AL.com in March that teams reached out to him during the season to gauge his interest in playing again but that he told them he did not foresee that.

"I heard from a couple of teams, just kind of checking in," Rivers told AL.com. "I didn't contact anyone and I'm not going anywhere. I think maybe some teams, with some guys going down, may have been just looking for a contingency plan."

At the time, a more realistic option for the Niners appeared to already be on the roster. After Garoppolo's injury, both he and the team held out hope he'd be able to play again if the Niners made it deep enough into the postseason.

And while Garoppolo did not make it back in time for the NFC Championship Game, he remained optimistic that he would be available had the Niners advanced.

"I was doing my thing, trying to get my foot ready," Garoppolo said Thursday. "It didn't work out how I wished it would have."

Garoppolo and the Niners had a reunion of sorts Thursday as the 49ers and Las Vegas Raiders are holding joint practices in Henderson, Nevada, before Sunday's preseason opener between the teams.

The Raiders signed Garoppolo to be their starting quarterback in March after the Niners made clear that there was no scenario in which they could bring back Garoppolo, especially from a financial standpoint.

Shanahan reiterated Thursday that his simple answer when asked whether Garoppolo could return was not meant to brush aside what the quarterback did for the organization.

"I think Jimmy was unbelievable for us," Shanahan said. "We won lots of games. I think that was a simple question. Is there a scenario where he'll be back here next year? And I give a common sense answer, and no. I think that was a little overblown on trying to be a shot at him or anything. We knew Jimmy wasn't coming back on his standpoint and our standpoint financially and everything. So that was just the common sense answer. But anytime I've been asked about Jimmy and what he meant to us and how he was, I've never said it differently. Jimmy was unbelievable here."