That doesn't mean Lance won't see the field this season. The No. 3 overall draft pick brings a different dynamic to head coach Kyle Shanahan's playbook, which has been evident in training camp. Lance, unlike Garoppolo, has been a part of several designed runs and shown that he can improvise his way out of the pocket to avoid pursuing defenders.
Fans can expect to see some in-season plays designed exclusively for Lance, which means taking Garoppolo off the field for those snaps. So how does the veteran quarterback feel about that? He had some mixed reactions.
"I've never been part of that," Garoppolo told Michael Silver of NFL Network. "I mean, if it could help the offense, help the team, I think that would be a good thing. I think when you get into that two-quarterback system, it gets tough at times, but we'll see when we get there."
The experience would be new for Garoppolo, who has only come off the field for the 49ers due to injuries. There are scenarios, though, where he can see giving way to Lance as a benefit.
Added Garoppolo: "If you could do it third-and-short, red-zone, things like that… I think it could help your team a lot."
Garoppolo spoke with reporters after Tuesday's practice and was asked what stands out about his rookie protégé.
"I think that the athleticism he brings and things like that," Garoppolo answered. "Me, Josh (Rosen), and Nate (Sudfeld) were kind of joking about it. He just pushes us to be better athletes, in a way. It's a different style, and so it's kind of pick your flavor that you want to."
In May, general manager John Lynch revealed when he could really see Shanahan's excitement about the idea of drafting Lance. It came while traveling back from Columbus, Ohio, after watching Justin Fields work out.
"I remember coming back from Ohio State, and Justin Fields had had a fantastic workout," Lynch said. "But on the way back, we're on the plane ... and Kyle's on his iPad with that [Apple] Pencil, and he's just grinding over there.
"Finally, he said, 'Look at this.' I was wondering what he was doing. Well, he was drawing up stuff with Trey in mind. We had just come from Justin Fields' (workout), and we both agreed his workout was fantastic. But that's when I said, 'He's really all in on this.' And the excitement he had, because he's doodling there, drawing up plays with Trey in mind."
Linebacker Fred Warner knows how challenging it can be to face a quarterback like Lance, who can do just as much damage with his legs as with his arm.
"That's always a stress on a defense," Warner said on Tuesday. "... Let's say we play like the Ravens where we have Lamar Jackson or any type of running quarterback that's a threat. You spend literally all week on trying to prepare for something like that because everybody has to be on point in their assignments for the play to be executed on our side.
"For our defense, going against Trey, that's giving us a great look at getting that work in, doing those types of plays. It does cause a threat to a defense when you have to worry about that on any given play."