It's not just the first NFL game in which he's ever played. It will be the first NFL game he's ever attended.
Garoppolo's family is scheduled to be in attendance for the occasion, coming in from Chicago.
"It's the thing we've been working towards," he said Wednesday after a walkthrough practice. "You get a couple of them and you have to take advantage of your opportunities. I'm trying to go out there and perform my best tomorrow and see what happens."
Garoppolo has had expected rookie struggles on the practice field, such as an interception in 11-on-11 drills Tuesday in which Washington cornerback Bashaud Breeland undercut a throw to the left sideline.
When a reporter extended an olive branch to him after Wednesday's practice, noting that most rookie quarterbacks struggle, Garoppolo didn't take it.
"It's one of those things, you don't want to accept failure," he said, later adding that his transition to the NFL has been what he expected. "You just want to keep progressing in the right direction. I'm a rookie and I have a lot to learn still. If I keep doing that, I'll be all right."
Along those lines, Garoppolo is not expecting that he'll have any butterflies before Thursday's game.
"It's still football. [The] football field is 53 wide and 100 yards long -- same old, same old. Just have to go out there and do it now," he said.