When Dean Wormer informed John Blutarsky that his GPA was “zero point zero,” Blutarsky, pencils in nose, shrugged as if to acknowledge that sounded about right.

49ers quarterback Jimmy Garoppolo had a similar reaction last night, after turning in a dreadful performance in his first game back after last year’s ACL tear. Except without the pencils.

Garoppolo posted a 0.0 passer rating, as low as the scale goes, in his first game back. He was 1-of-6 for no yards, with an interception in his limited work. Coming off a five-interception practice last week, you’d think he’d be more worried, but apparently not.

“Obviously a little frustrated but it’s the NFL,” Garoppolo said, via Jennifer Lee Chan of NBCSportsBayArea.com. “Unfortunately, we don’t get to play the whole game right now so I only get so many plays. You wish you could be out there for more so we could bounce back. But it is what it is. It’s preseason right now, so we just have to take it in stride.”

He didn’t stride long, though part of that was his fault. His second pass was picked off, and he then presided over a pair of three-and-outs, before yielding, mercifully, to C.J. Beathard.

Coach Kyle Shanahan looked on the bright side, saying the experience was good if the results weren’t.

“Yeah, of course,” Shanahan said. “He’s had a year off football, and before that he only played about eight games total. The more he can play, the better. I wish we could have kept him out there longer today but you risk everyone else too, so I had to get those guys out of there. . . .

“Anytime you can’t get an offensive rhythm, everyone looks that way. We didn’t get anyone in rhythm. I wish we could have gotten him in a rhythm. It was very hard to pull him off on the third series because we wanted to go one and two series. One and two good series.”

Pretty soon, he’s going to have no choice but to leave Garoppolo out there. And the results need to improve, and quickly, or else Garoppolo and wife Mandy Pepperidge will be heading to the U.S. Senate sooner rather than later.