The San Francisco 49ers round off their regular season against the Los Angeles Rams in Week 18 in a game in which the backups will likely see the bulk of the action.

Though the Niners, having secured a first-round bye in the NFC playoffs, are keen to avoid rust, there is little need for them to play their starters for an extended period of time.

Kyle Shanahan on Wednesday confirmed starting quarterback Brock Purdy will not play versus the Rams, who are resting Matthew Stafford along with the likes of Aaron Donald, Kyren Williams and Cooper Kupp.

As such, the focus will not be on the result or any of the players set to play key roles in the postseason, but on reserves aiming to show they can make a positive impact in the playoffs.

QB Sam Darnold

After 16 straight games of Purdy, Darnold will get his chance to prove what he can do in a full regular-season contest in the Kyle Shanahan offense.

For somebody of his remarkable arm talent, it promises to be a fascinating experiment. Though he threw an interception on a desperation heave, the flashes were promising in his second-half action against the Baltimore Ravens on Christmas Day.

Playing against the Rams backups, the conditions should be ripe for Darnold to excel. If he does, the 49ers will have reason to feel very confident about their second-string quarterback going into the postseason.

WR Ray-Ray McCloud

Back after a five-game spell on the sideline with a rib injury, kick returner McCloud essentially gets a free hit to ready himself for the playoffs with no pressure riding on his performance. The Niners will want him to show the dependability they have lacked in the punt return game in his absence.

TE Brayden Willis

Essentially promoted to the third-string tight end spot after Ross Dwelley was placed on injured reserve to make room for McCloud, seventh-round rookie Willis will likely see his first extended action of 2023 and could be asked to operate at tight end and fullback with Kyle Juszczyk added to the injury report with an illness. Willis aligned as a fullback regularly at Oklahoma.

The former Sooner has shown positive flashes as a blocker in garbage time. It will be interesting to see if he can impress over more sustained playing time.

G Aaron Banks

Banks only played special teams last week because of a toe injury. With Jon Feliciano nursing a back injury, the left guard is likely to be one of the few San Francisco starters that plays deep into the game. 

At the end of a second half of the season that has been disrupted by his troublesome toe, how Banks holds up bears watching closely.

DT Sebastian Joseph-Day

The former Los Angeles Chargers defensive tackle played 11 snaps in his debut for the 49ers last week against the Washington Commanders, but head coach Kyle Shanahan had high praise for his efforts.

Shanahan said in his Monday conference call:

"It was good to get him out there. We definitely liked the guy and liked the player. [We're] asking him to do some totally different stuff. So the style that he's played with, with two gaps and his stances and stuff, are just kind of the opposite of what we do. So to get him really a half practice, where he just got to work on a couple of things full speed for two periods, and then for him to go out there and play those 11 plays, I was real impressed with him. He was ready to go, did everything we asked, and I bet you he'll get a little bit more playing time than that next week."

Taking on the team that drafted him this week, the 49ers will give Joseph-Day extended playing time in the hope he can prove himself a viable option on the interior defensive line if Arik Armstead is unable to recover from foot and knee injuries in time for San Francisco’s Divisional Round matchup.

DE Robert Beal Jr.

The 49ers’ depth at edge means their fifth-round rookie hasn’t seen much action since being activated off injured reserve, but he’s demonstrated some promise when he has got on the field with his get-off and ability to translate speed to power. 

Beal likely won’t see many defensive snaps in the playoffs, but Week 18 is an opportunity to prove the Niners can rely on him if required.

CB Darrell Luter Jr.

Whenever he’s gotten the chance, defensive coordinator Steve Wilks has raved about Luter, his maturity and his approach to preparation.

He’s only been targeted three times this season but hasn’t allowed a reception on any of those targets. When the 49ers’ starters exit the game, Luter will get a shot to vindicate Wilks’ words of praise.

CB Isaiah Oliver

Given the injuries to starters Ji’Ayir Brown and Tashaun Gipson, Oliver would have seen a lot of work at safety had Jason Verrett not suffered a torn rotator cuff in practice this week, robbing him of the chance to receive prolonged playing time at nickel.

With Verrett done for the year, Oliver may end up playing safety with the starters and then pivoting to nickel when the likes of Charvarius Ward, Deommodore Lenoir and Ambry Thomas head to the bench.

He may be a busy man, but it’s a chance for Oliver to demonstrate his versatility in being able to play two spots and, more importantly, ease any concerns the 49ers might have about him playing nickel after essentially being benched from that role after the Week 9 bye.

49ers rookie set for big Week 18 role after roster moves

He may get a big opportunity.