SANTA CLARA, Calif. -- It was about a month ago that San Francisco 49ers general manager John Lynch and coach Kyle Shanahan began having conversations about what a scenario in which quarterback Jimmy Garoppolo remains with the team might look like.

By that time, Garoppolo's right shoulder surgery had ruined any chances of an early offseason trade and, as Shanahan put it Tuesday, the NFL's game of quarterback musical chairs had stopped with most of the other seats filled.

In the first week of camp, Shanahan expressed to Garoppolo that if nothing materialized elsewhere, the team would love to welcome Garoppolo back on a reduced contract to be the backup to first-year starter Trey Lance.

Even then, Shanahan, Lynch and the Niners never thought what happened Monday -- when the Niners and Garoppolo agreed to a re-worked one-year contract worth about $7 million and up to $16 million with incentives -- was a real possibility.

"The chances were, to me, it seemed slim to none," Shanahan said. "I remember the first week of training camp me saying to Jimmy like, 'Hey, if you don't like any of these opportunities, if you don't go to the place you want, you can't get the contract that you want, we would love to have you here as a backup in that deal.' I want you to know that we feel that way but I also think there's no way you're not gonna get something as this goes throughout training camp."

The belief by both the Niners and Garoppolo was so strong that he would be playing elsewhere that Garoppolo continued his recovery throwing program on the side while the Niners practiced on neighboring fields.

And while Garoppolo was welcome to attend team meetings and practices, he stayed away because of the belief that he'd be playing elsewhere, be it from an injury leading to a trade or a team becoming unsatisfied with its quarterback options.

But as the weeks went by and Garoppolo remained in San Francisco, that never happened. The Cleveland Browns seemed to be a logical landing spot with the suspension of Deshaun Watson but they never made an offer, perhaps joining a list of other teams waiting for the Niners to release Garoppolo before Tuesday's cutdown to initial 53-man rosters.

According to Shanahan, that's exactly what the Niners would have done had Garoppolo not agreed to reduce his salary cap number by nearly $18 million for 2022.

"To me, it seems like everyone was just waiting for us to cut him so they could see how much they could get him for," Shanahan said. "But once the last Saturday preseason game happened and no one got injured, then Jimmy thought this was his best situation that he liked. And that's why we were so pumped because it's obviously a better situation for the Niners.

"We were always clear to Jimmy that salary cap wise and a backup role and supporting Trey and that if that worked for him, that was a no brainer for us. We just didn't think the chances of that were gonna happen. And it ended up being that way. And so, when it was all said and done, even though it was pretty shocking to us, we thought it was a win-win for both sides."

From the Niners' perspective, keeping Garoppolo came with multiple advantages. First and foremost, it improved their backup situation behind Lance, who has started just two NFL regular season games. Since Shanahan arrived in 2017, the Niners are 35-16 when Garoppolo starts (including the postseason) and 8-28 with any other signal caller under center.

The Niners intend to keep rookie Brock Purdy as the No. 3 quarterback, which likely leaves veteran Nate Sudfeld as the odd man out.

It also extends the 49ers window to potentially trade Garoppolo should another team have a need for a starting quarterback arise before the Nov. 1 trade deadline. Garoppolo's contract does include a no-trade clause, which means the situation would have to be appealing enough for him to approve any deal.

For Garoppolo, it means the opportunity to stay in a familiar place in a system in which he's had success while also rehabilitating his value to other teams before entering free agency in the offseason. Essentially, it eliminated the chances of Garoppolo going to an unknown situation in which myriad variables could make it harder for him to land in a good spot in 2023.

It also gave Garoppolo a longer runway to get his right shoulder healthy knowing that missed practices and meetings won't throw him off too much because he's already familiar with Shanahan's system and his potential pass catchers.

"While doctors cleared him with no restrictions, there was the added caveat that it would be a smart thing to, to really build him up," Lynch said. "And this allowed him to do that and not be rushed on the field. Sometimes stuff just happened and so more of a controlled environment...

Jimmy's played a lot of football. We believe he's ready."

Indeed, the Niners plan is to get Garoppolo back to practice right away with Shanahan acknowledging that Garoppolo will be Lance's backup for the Sept. 11 season opener against the Chicago Bears with Purdy as the No. 3.

Shanahan said Tuesday that he had conversations with Lance about Garoppolo returning before the move was made and that Lance was "great" about it and had "no problems with it at all." The Niners' hope is that Lance and Garoppolo can be good for each other this season even in a role reversal this year.

The question, of course, is how all of that will manifest if and when Lance struggles and Garoppolo is waiting in the wings. Shanahan reiterated Tuesday that this is Lance's team and he will get the chance to play through his mistakes.

"We feel very strongly giving the keys to Trey," Shanahan said. "We were really excited what we thought that could do for our team as a whole. And we're excited about everything he's done and all these opportunities gone throughout this season. And I can't wait to get him started on our team in week one. And having Jimmy there as a backup makes us feel really good because we have a starting quarterback as a backup. The rest of the league had a chance to get him and I just so feel so fortunate that he's still here in that case."