The NFL regular season is almost upon us, but first, one last preseason tune-up for the Seahawks and the rest of the league before Saturday's deadline to reduce rosters to 53 players. When the Seahawks play at Oakland Thursday night, many of their top players might be held out of the game or see very limited playing time, but that doesn't mean there still isn't plenty at stake. The Seahawks have to trim their roster by 22 players this weekend, and some of those final roster spots have not yet been decided, which means for players battling for those jobs, this is a final chance to prove themselves, or at the very least to show other NFL teams their worth if they do hit the waiver wire Saturday.

Here are five things to watch in for the Seahawks in a game that will still have plenty of meaning, even if it lacks in star power:

1. C.J. Prosise trying to play catch-up.

Rookie running back C.J. Prosise made his preseason debut last week after missing the first two games with a hamstring injury, but saw limited playing time both because he was working his way back after a long layoff, and also because Christine Michael saw much of the playing time with the starters playing into the third quarter. This week, however, Prosise will "play quite a bit," Seahawks coach Pete Carroll said, and those snaps are important both for Prosise and Seattle's offense. When drafting Prosise, the Seahawks envisioned the third-round pick stepping into a prominent role in the offense right away as their third-down back, and while Prosise still has a good chance to hold down that role this season, he needs to show in extended game action that he can handle the responsibilities of that job as well as hold up physically.

"This is really important for me," Prosise said. "I just want to go out there, keep getting better and keep learning this offense better and perfecting my craft to get ready for the season."

Coaches like what they've seen from Prosise since he returned from his injury, but they still need to see more of it.

"C.J. has done nothing but positive stuff," Carroll said. "Everything he has done looks good, so we're excited about it. But he just needs game time."

Added offensive coordinator Darrell Bevell: "He has continued to progress. He's done great throughout this week. We really like what we saw last week. You saw him make some nice runs, get the ball in his hands a couple times. We will continue to see that; I think we want to get a little playing time out of him this game and see if he continues to progress that way. We've talked about it. He's done a really good job mentally and all those mental reps that he was able to take, he was doing that and he was doing a nice job of that. It's been able to carry over onto the field."

And Prosise won't be the only rookie back taking on a big workload Thursday. Carroll said fifth-round pick Alex Collins will also see significant playing time.

2. Roster hopefuls and their last chance to impress.

While there aren't many starting jobs up for grabs at this point in camp, there are still tough roster decisions to make on both sides of the ball. Seattle's depth in the secondary means some good players will have to be let go; receiver is still unsettled beyond the top four players; tight end is hard to handicap, especially with Nick Vannett battling an ankle injury and Jimmy Graham's Week 1 status still in question; and the final spots on both lines, at linebacker and at running back could all still be up for grabs. In other words, there's still a lot to sort out between now and Saturday.

"You know it's always exciting to watch and see how they're able to rise to the occasion," Bevell said. "The one thing we always talk about them doing is just playing the way that they're capable. We don't need them to go make spectacular plays to try to make the team because that's usually when that kind of thing doesn't happen for them. It's when they play within the scheme and do the things that we ask them to do. That's when they really excel and that's what we will be looking for."

3. The final push at right tackle.

While some starters won't play much if at all, the Seahawks very well could take a longer final look at their offensive line, and particularly at the battle going on at the tackle spots between Bradley Sowell, J'Marcus Webb and Garry Gilliam. Sowell seems to have the edge at left tackle, but that's not set in stone, while Webb and Gilliam are fighting for the starting job at right tackle.

"We have a competition at that spot, which is good," Carroll said of right tackle. "This game will be important again for those guys. We think both of those can play right now, so we're in good shape there."

The Seahawks can rest a player like Russell Wilson or Earl Thomas or Richard Sherman or Michael Bennett or Bobby Wagner because they know exactly what they have at those spots; the same cannot yet be said about some spots on a new-look offensive line.

"There's still a battle going on up there," Bevell said. "I feel like the inside three is pretty solid and Bradley has done a nice job at left tackle. We're still taking a long look at the right tackle position, give both of those guys an opportunity to continue to compete for it and we'll see how it shakes out."

Or as offensive line coach Tom Cable put it earlier in the week, "I like what's going on at the tackle spot, but it's still unsettled."

4. Trevone Boykin and Jake Heap's final, and likely lengthy, preseason audition.

All signs point to rookie Trevone Boykin opening the season as Seattle's No. 2 quarterback, but that doesn't mean he can't do more both to show that he's ready for that job. Boykin has done a lot of impressive things in his first NFL preseason, from the obvious moments like leading a final-minute comeback drive at Kansas City, to more subtle growth such as cleaning up some pre-snap issues. Now he has one more preseason game to show he is continuing that growth.  

"He's growing," Bevell said. "I think as any young quarterback, there's a lot on his plate with what we ask him to do. He's continuing to grow. I think with that being said, he has performed well. There's obviously things that he can do better and improve on. We're working on each and every one, every day. I like the progression that he's made. He's really done a nice job of picking up the offense but there's so many nuances, whether it's the protections and those types of things. It's important for him to continue to stay on it and not get complacent and make sure he's focusing on it. Which he is."

For Heaps, who has quietly had a very solid training camp, this is a chance to show the Seahawks, or perhaps another team, what he can do in what should be more playing time than he received the past two weeks when Wilson and Boykin played most of the snaps.

5. The last chance for receiver depth to shine.

Coming into training camp, Carroll and other coaches pointed to receiver as a deep position groups that would force them to make tough decisions when it came time to set the roster. Doug Baldwin, Jermaine Kearse, Tyler Lockett and Paul Richardson all seem like safe bets to make the team but that final spot or two at receiver looks to be about as open now as it was four weeks ago. Part of the reason things remain so unsettled is that injuries have made it hard for the Seahawks to get a good evaluation on the entire group. Kevin Smith, who was on the 53-man roster for part of last season, was waived/injured Tuesday because of a hamstring injury, as was Deshon Foxx. Undrafted rookie Tanner McEvoy has been impressive, also doing work at tight end, but he too has been limited by a groin injury this week, though he could play Thursday, Carroll said. Another player on the roster last year who has battled injury is Kasen Williams, but he too could be back Thursday, and if he does, this would be a very important final game for him if he is going to pass a player like Douglas McNeil III or rookie Kenny Lawler, who have been healthy.

"We want to see them go out and perform the way they're capable of performing, and then make the plays when they have the opportunities to make them," Bevell said. "It's not just going to be this one game. There's a great body of work with the other three preseason games, all throughout training camp, OTA's, minicamp. So we've got a good look at a lot of these guys. This is just one more opportunity for them to get out there in live game situations and perform at their best."