That's because the 49ers had never practiced that play. In fact, Shanahan's playbook was void of a QB sneak all together. So how on Earth did Garoppolo end up keeping it himself? He called his own number, of course, and here's why.

On the previous play, Kyle Juszczyk caught a 17-yard pass and took it all the way to Jacksonville's 1-yard line. Garoppolo's initial thought was that his fullback had scored.

"I was borderline celebrating, and then I saw that he was just short," Garoppolo recalled.

What felt like "just short" was a full yard in reality. Juszczyk hobbled back to the huddle after getting banged up on the reception. After a quick hesitation, he pivoted and ran back to the sideline to get looked at by the training staff. Mitchell – yes, the 49ers 310-pound nose tackle – came sprinting into the game to play fullback in front of Carlos Hyde.

This wasn't completely random. Mitchell practiced with the 49ers offense each Friday during goal line work. There were three-to-five plays each week that included Mitchell, but that package was never utilized up until this point.

"All of a sudden Earl was running in," Garoppolo said. "I looked up at the play clock, and it was already down to 16 or 17 seconds. The comms system goes out at 15 seconds. I remember seeing Kyle (Shanahan) on the sideline super animated getting people in, yelling at coaches or whatever it was. Then he looks at me, and once he started to call the play, I hear, 'I-right' and then this beep goes off and the sound goes out."