Raiders' backup quarterbacks Matt McGloin, Connor Cook in the spotlight Thursday

ALAMEDA - The Raiders' preseason game against Seattle means nothing in the big picture other than being the final hurdle before the regular season.

For backup quarterbacks Matt McGloin and rookie Connor Cook, it means a whole lot more.

With Derek Carr almost certain to sit out against the Seahawks, the Raiders will lean on McGloin and Cook to share the quarterback duties in what will be their last extended workout before the regular season begins.

One of the two will be Carr's primary understudy. Although McGloin seems to have the edge, coach Jack Del Rio and his staff haven't made an official announcement, which puts an added emphasis on Thurday night's game at the Oakland Coliseum.

"You just let everything out," Cook said Tuesday. "All the stuff that I have learned thus far, go use it. This is the time to cut loose and have fun with the guys. We know there's going to be cuts after this game and once the season starts the reps are going to be very miniscule so we're just going to go out there and have fun."

Del Rio hasn't revealed the quarterback rotation for Oakland's preseason finale but McGloin is expected to start while Cook, a fourth-round draft pick this year, is expected to come off the bench late in the first half and play the remainder of the game.

The Raiders are likely to keep both players on the 53-man roster so the game against the Seahawks is more a formality than anything else.

Still, the two quarterbacks understand the significance of what playing well could mean in the big picture.

Both have had moments where they've played well and each has also struggled.

"That's the thing about preseason, you have a limited amount of reps so it is crucial for you to get in there, get a couple of completions early and get into a nice rhythm," McGloin said. "Preseason or not, practice or not, it's always important as a quarterback to get into a great rhythm, find completions and get that confidence built up."

McGloin has been the Raiders backup quarterback since entering the NFL as an undrafted free agent in 2013. He started six games as a rookie but has played in only three since then.

The former Penn State standout has had mixed results this preseason after signing a $2.55 million second-round tender with Oakland. McGloin threw a pair of touchdown passes against Arizona in the preseason opener but has failed to match that since. He attempted only five passes against Green Bay then went 8 of 13 versus Tennessee last week but threw an interception and had a 44.1 rating.

"I've done some good things, I've done some things that definitely need improvement on," McGloin said. "You can always improve on decision-making, always improve on your checks and things like that. It's just continuing to get better every day."

Cook, who holds almost every meaningful passing record at Michigan State, got off to a slow start with the Raiders and is coming off a game in which he was intercepted twice while completing 16 of 26 attempts.

"The comfort level that I have now is head and shoulders above where I was in minicamp and OTAs," Cook said. "With limited reps it's hard as a quarterback. For any of the quarterbacks, even starters who get in there and play three series and then they're done. As a quarterback you need to establish a rhythm. It could take you a quarter, it could take you maybe a half. It's just how it is at the quarterback position."