3 Things to Watch in 49ers' Preseason Finale vs. Raiders

The San Francisco 49ers have one preseason game left.

For most of the players expected to lead them this season … that's probably not particularly important.

Kyle Shanahan said he would be "surprised" if many starters take the field Thursday against the Las Vegas Raiders. San Francisco has bigger things coming — including an unusual Week 1 trip to Australia to face the Los Angeles Rams.

For everyone else?

Thursday could mean quite a bit.

The Niners will trim their roster from 90 players to an initial 53 on Sunday, and injuries have made some of those decisions more complicated than San Francisco would probably prefer. Twenty-three players on the 90-man roster did not participate in Tuesday's final full training camp practice.

So, no, the final score in Las Vegas isn't particularly important.

But these three things are:

If there is one starting job that could actually be affected by Thursday's game, it's left guard.

Connor Colby, Carver Willis, Robert Jones and Austen Pleasants all remain in the mix. Jones is currently sidelined with a calf injury, while Pleasants is dealing with a knee injury. Colby and Willis are both expected to play against Las Vegas.

That gives the Niners another chance to evaluate the two healthy options before Week 1.

Shanahan isn't pretending the decision can wait much longer.

"It's close to being decided, and it needs to be close," Shanahan said. "Today is the second-to-last day that we'll get to evaluate. We'll get it on the game."

So … here comes the game.

Injuries have prevented San Francisco from getting the clean month-long competition it probably wanted. Willis missed time earlier in camp, Jones is now sidelined and Pleasants injured his knee against the Los Angeles Chargers.

The Niners don't necessarily have to leave Las Vegas announcing their Week 1 starter.

They'd probably prefer to leave knowing who it is.

Twenty-three players.

That's how many members of San Francisco's 90-man roster missed Tuesday's final full practice … and that's quite a number to be dealing with days before roster cuts.

Some of those absences aren't expected to linger. Shanahan hopes Nick Bosa can return to practice next week, while Mike Evans, Upton Stout and Jacob Cowing are also expected back. Others could force the Niners into more complicated decisions involving injured reserve or the PUP list.

That's where Thursday matters.

With Shanahan not expecting many starters to play, the finale should provide plenty of snaps for players who don't yet have the luxury of looking ahead to Week 1.

And making Sunday's initial 53 isn't necessarily the finish line.

"I always tell everyone the final 53, all that means is the final 53 that day," Shanahan said. "This is the NFL. You are having to prove this every single day."

For some of the players taking the field Thursday … there might not be a better opportunity to do it.

San Francisco has questions to answer in the secondary, too.

Malik Mustapha remains sidelined with a hamstring injury, leaving another opportunity at safety alongside Ji'Ayir Brown. Marques Sigle is among the players with a chance to make his case Thursday, while veteran Ashtyn Davis gives San Francisco another option.

Sigle gave the Niners something to like Tuesday, intercepting a tipped pass during the team's final full training camp practice.

Cornerback has its own questions.

Renardo Green is sidelined with a hamstring injury, Upton Stout is dealing with a hip flexor injury and Nate Hobbs remains out with a groin injury. Stout is expected back at practice next week, but those absences create more opportunities for the rest of San Francisco's cornerback room.

Jack Jones made his case Tuesday with two pass breakups during one-on-one drills.

Now he, Sigle and the rest of San Francisco's secondary depth get one more preseason game to make it.

The Niners aren't going to learn much from the scoreboard Thursday night.

They could get closer to deciding who starts at left guard, who survives the initial cut to 53 and who they can trust in a secondary carrying several injury questions into September.

For a preseason finale … that's plenty to play for.