AJ McCarron getting acquainted with backup QB role behind Derek Carr

AJ McCarron has played in 11 NFL games since coming into the league in 2014. AP Photo/David Richard

ALAMEDA, Calif. -- As shocking as the Khalil Mack trade was ...

As mystifying as the Martavis Bryant cut came to be ...

And as, ahem, brilliant as getting something in return in trade for Shalom Luani, a player they were going to cut anyway ...

The Raiders jettisoning backup quarterbacks EJ Manuel and Connor Cook, who were already schooled in coach Jon Gruden's notoriously complicated offense, in favor of acquiring journeyman backup AJ McCarron, who knew next to nothing about "Spider 2 Y Banana," should have caused almost as much consternation.

Or have you forgotten Derek Carr suffering broken bones in his passing pinkie finger, right leg and back the past two seasons?

"Hopefully, Derek stays healthy, that's No. 1," Gruden said after McCarron was acquired on Saturday. "We have to fast-track AJ ... and he'll be a consistent visitor here at this facility for the next few weeks. He's got a lot of catching up to do and we'll try to fast-track him the best way we can.

"There is a possibility that we bring another arm in here, so we'll see."

On one hand, if you were going to start from scratch with a journeyman backup quarterback who knows nothing about your system, wouldn't you want one with a track record as a playmaker who is already on the street? That, at least, wouldn't have cost a fifth-round draft pick, as the Raiders sent to the Buffalo Bills to acquire McCarron.

"I like McCarron," Gruden said. "I think a lot of people in the league like McCarron; that's pretty obvious. He's got big upside. We'll try to get him ready if need be."

If nothing else, McCarron, a fifth-round pick of the Cincinnati Bengals in 2014 who has played in all of 11 NFL games and was 2-1 in three 2015 starts, will see a few familiar faces with the Raiders.

For one, there's new Raiders radio broadcaster Brent Musburger, who infamously leered after McCarron's future wife, Katherine, during the 2013 BCS national championship game broadcast and then this week famously welcomed the couple to Oakland in a tweet.

"Oh, that's awesome," McCarron said Thursday with a chuckle. He was not aware of the welcoming social media post.

McCarron has been putting in early mornings and late evenings with Raiders QB coach Brian Callahan in trying to get a grasp on Gruden's offense. And even though McCarron's former wideout at Alabama is in Oakland, Amari Cooper is not really an asset ... yet. Not with Cooper a starter and McCarron toting around the playbook.

"He's always been a quick learner," Cooper said. "He's always, ever since I've known him, he's always known the offense, in and out. So I don't think it will be tough at all."

Plus, McCarron has Carr in his corner, and his ear.

"I'm here to help him, that's for sure," Carr said.

"He's here to compete with me every single day. That's what we did with Connor and EJ. We competed every day. Beat me in the drill. Throw a better pass than me. Do the feet better, all those kinds of things. We'll do those same things, but at the same time if he has any questions, any help, if he doesn't know where to go for lunch, that's what I'm here for."

McCarron signed a two-year, $10 million free-agent contract with a $4 million signing bonus with the Bills in March. He has a base salary of $900,000 guaranteed by Oakland this season.

And that's really the only guarantee when it comes to McCarron and the Raiders offense at this moment.

"I mean, it's different for me, coming from Buffalo," McCarron said of Gruden's system. "It's two totally different types of schemes, thought process, so it's definitely different but, I mean, you still run a lot of the same plays, no matter what system you're in.

"It's just lingo and formations and everything else you've got to get used to. It's just a learning process, and enjoy it."

And if he has to play in Monday night's season opener against the Los Angeles Rams, barely a week after arriving?

"God forbid I get in there; it's not going to be perfect," McCarron said. "But I know how to battle and keep trying."