THOUSAND OAKS, Calif. -- The Los Angeles Rams had many reasons to celebrate.

An NFC West title in hand, a playoff berth earned and another box checked on the way to their ultimate goal.

Yet as teammates and coaches posed for position-group photos inside the visitors locker room at Ford Field following a Week 13 victory over the Detroit Lions, Todd Gurley couldn't help but feel a tinge of disappointment.

Missing from action and unable to commemorate the division-clinching win was Malcolm Brown, Gurley's trusted backup the past three seasons.

Brown suffered a shoulder injury before halftime and did not return to the game. And as it turned out, Brown's injury required a procedure to reset his clavicle and he is likely headed to injured reserve, with an expected recovery time between eight and 10 weeks.

"Just losing a guy like him, a big piece for us, especially on special teams," Gurley said Thursday. "And I know I can come out comfortably in the game and he's going to go in there and do the same production."

Because of the spotlight on Gurley -- the reigning NFL Offensive Player of the Year and an MVP front-runner this season -- Brown's absence might go unnoticed to a casual viewer.

But Brown averaged 17.7 yards per game and has 212 rushing yards this season, and is a mainstay on special teams.

There's little doubt, as the Rams (11-1) play their final four regular-season games, that Brown's absence will felt by Gurley and the offense.

"He's been a guy that's stepped in and done such a great job and really been a guy that I've been able to rely on and have just as much trust in him as I do in Todd," quarterback Jared Goff said. "As far as protections and being in the right place at all times and just how smart he is and how good he is as a player with the ball in his hands and everything in between."

With a playoff berth secured, a victory over the Chicago Bears at Soldier Field on Sunday night would guarantee the Rams a first-round bye.

But the Bears will provide the greatest defensive challenge the Rams have faced this season. The Bears rank second in rushing yards allowed per game (85.8), fourth in total yards allowed per game (317.9) and fourth in points allowed (20.1). Not to mention Chicago has intercepted a league-high 21 passes.

"This is an excellent defense," Rams coach Sean McVay said. "You see why they're one of the top units in the league."

And while Gurley remains the star of the Rams' offense -- he has a league-high 19 touchdowns and leads the NFL in rushing yards, averaging 97.9 per game -- Brown provided reliable relief when Gurley has gone to the sideline.

When asked if Brown's absence would change his mindset about staying on the field, Gurley responded, "Oh yeah."

"For sure," Gurley said. "Little stuff like that factors in, you'd rather be on the field. But if I'm not, I mean not 100 percent, but if I'm in there dead tired, why not put another guy in that's going to give 100 percent effort rather than me half-assing the play."

The other guys Gurley and the Rams must rely on are second-year pro Justin Davis and rookie John Kelly.

The Rams signed Davis after he went undrafted from USC in 2017, and they selected Kelly from Tennessee in the sixth round of the 2018 draft.

"We have a lot of confidence in Justin and John to step up," McVay said. "And they'll be needed to and they'll be needed to do it in a hurry."

Both players provided a spark in the preseason, though Davis was sidelined for three of the four preseason games because of a hamstring injury.

But neither running back has played on offense in a regular-season game this season.

In fact, Kelly has yet to be active on game day, while Davis has been active for just eight games and played only on special teams.

"Everybody dreams about the opportunity to go out and see what they can do at the NFL level," Davis said. "It's always something I just kind of made sure I was ready for because anything can happen in the league and when my number is called I've got to be ready."

How quickly Davis and Kelly catch on could affect how much Gurley stays on the field down the stretch.

Last season, after the Rams secured the NFC West and a playoff spot in Week 16, McVay elected to rest his starters in a regular-season finale against the San Francisco 49ers in an effort to ensure they were well rested for the playoffs.

But a similar luxury might not be afforded as the Rams inch closer to the postseason.

The Rams are in control of NFC home-field advantage through the playoffs, but any potential misstep through the final four games could prove costly, with the New Orleans Saints just a game behind in the standings and having defeated the Rams head-to-head.

Depending on how reliable Gurley's new backups prove to be, McVay could come upon a difficult decision.

Rest his star back and refresh his legs or keep running Gurley to secure home field in the playoffs?