C.J. Beathard, the rookie quarterback for the San Francisco 49ers, is scheduled to start his fourth game of the season when the team hosts the New York Giants at Levi's Stadium on Sunday. The 49ers' potential quarterback of the future, Jimmy Garoppolo, stands on the sidelines as an observer while absorbing as much information about his new offense as possible.

Once Garoppolo is up to speed, and Shanahan feels comfortable enough in his grasp of the offense, the new 49ers quarterback will likely see the field. Until then, the only way Garoppolo gets behind center in a game is if Beathard isn't able to.

While Shanahan insists Beathard is his starter this week, the 49ers still have three days worth of practices ahead of them and, of course, the head coach reserves the right to change his mind.

"It's day-to-day," Shanahan said of Garoppolo's progress. "We're throwing a lot at him."

Not only does Garoppolo have to learn the foundation of the playbook, but he has to learn the different game plans each week, which is based on that foundation. Most quarterbacks have an entire offseason to learn what Garoppolo started studying on October 31 after flying in from the East Coast. He's had just over a week to learn what Beathard has been studying since late April.

"He came in last week, crammed in the verbiage, worked as hard as you could at it," Shanahan said. "We had a plan for him last week, if we needed to him, that he was ready for. He came in Monday, started working again. Much farther ahead on Monday than he was last week. He's a smart guy and works at it so he's much further ahead now than he was last week."

Shanahan was asked if Garoppolo could still possibly start on Sunday against the Giants.

"I'll consider everything," Shanahan responded. "I'll watch how practice goes. I'm still thinking a lot more similar to how it was last week. Just where we're at, where they both are. But it's a day-to-day thing right now, and we're planning for it all."

"I'm eager (to play)," Garoppolo told reporters on Wednesday. "Coach has a good plan set up, though. Whatever he wants, I'll be ready to perform."

Shanahan hoped Garoppolo could play on Sunday against the Arizona Cardinals. The situation got to the point where, if the quarterback were needed, the team would be able to insert him into the offense. Had Beathard needed to exit the game, the head coach said you would have seen him rip up his play call sheet and get a new, more limited one specifically tailored for Garoppolo.

"Hopefully [he plays] sooner than later, but I'm not setting a date on it," Shanahan said.

Shanahan will see where Garoppolo is on Friday following the team's three full practices this week.

As for Beathard, Shanahan said he is committed to his rookie starting on Sunday and fully expects him to start. Beathard is scheduled to receive all of the starting reps in practice this week.

"I plan on going with C.J.," Shanahan said. "We'll see how practice goes."

Beathard took a beating against the Cardinals. He's not worried about public perception that he's out there getting hit so Garoppolo doesn't have to. Beathard said on Wednesday that he blocks all of that out.

"All I know is I'm trying to do my best and get better," Beathard told reporters. "The coaches have the team's best interests in mind. I think I trust them and I trust my team to get back to work this week and work to get a win."

* Videos courtesy of Cam Inman of Bay Area News Group.