Gary A. Vasquez-USA TODAY Sports

The Week 15 edition of "Thursday Night Football" features a battle of AFC West foes, as the Los Angeles Chargers welcome the division rival Kansas City Chiefs to SoFi Stadium for a showdown that will have considerable implications for the playoff race. 

Kansas City has re-staked its claim to the top of the division by winning six consecutive games, spurred by a defense that has allowed just nine points in each of its last three contests and hasn't allowed more than 17 since Week 7. Los Angeles has won four of its last six games, and of late its offense has been firing on all cylinders, totaling 78 points over the last two weeks and scoring 37 or more in three of the last four. 

The Chiefs enter this game at 9-4 and the Chargers at 8-5, with Los Angeles holding the tiebreaker by virtue of having won the first matchup between these two teams. Will Kansas City solidify its hold on the division by taking a two-game lead, or will L.A. make things a whole lot more interesting by evening up their respective records and ensuring that their rivals will have to finish the season a game ahead in order to actually take the division crown? We'll find out later this evening. For now, let's break down the matchup. 

How to watch

Date: Thursday, Dec. 16 | Time: 8:20 p.m. ET
Location: SoFi Stadium (Inglewood, California)
 Fox/NFLN | Stream: fuboTV (click here)
Follow: CBS Sports App
Odds: Chiefs -3, O/U 52

When the Chiefs have the ball

The Chargers defense provides a very specific kind of test for Kansas City. Head coach Brandon Staley heavily utilizes the types of light-box defensive fronts that have given the Chiefs trouble throughout this season, essentially daring opponents to either run the ball or repeatedly take underneath throws in order to matriculate their way down the field. The Chiefs have been better about taking up that kind of challenge in recent weeks, though it's notable that their two best offensive games over the last two months (by far) have come against a Raiders defense that plays the complete opposite style. 

Only one NFL team (Staley's former team, the Rams) has faced more opponent rushing attempts into a light box than have the Chargers, whose opponents have run it 201 times, according to Tru Media. L.A. has yielded 5.4 yards per carry on those plays, the ninth-worst mark in the league. The one thing Staley's unit has done fairly well against the run game when aligned this way is take away explosive gains: 9 percent of opponent carries with six or fewer defenders in the box have gained 12 or more yards, a rate right around league average. They have rarely stopped plays in the backfield (9.5 percent, sixth-worst in the NFL) or held the rusher to a gain of fewer than five yards (46.8 percent, third-worst). 

The last time Kansas City had what you'd even charitably describe as a great rushing performance against light boxes, though, was back in Week 6 against the Football Team -- and they only ran it 14 times for 77 yards. Since then, they have not exceeded 4.8 yards per carry into a light box in any game. (The NFL average is 5.0 per carry in those situations.) Can they do better against the Chargers? Perhaps funneling more of the work to Clyde Edwards-Helaire (4.9 per carry) than Darrel Williams (4.1) would help, but either way, they seem unlikely to find a dominant rushing performance, considering they have not done so for nearly two seasons now. 

Instead, it'll likely be up to Patrick Mahomes to work the underneath areas of the field. That may be made easier for him if Derwin James, currently listed as questionable, is unable to suit up. James figures to spend a lot of time on Travis Kelce if he plays, and if he doesn't, Kelce will surely have an easier go of things. Kelce has exactly three catches for 27 yards in each of Kansas City's last two games, and has totaled less than 70 yards in seven of the Chiefs' 10 most recent outings. He went off for 7 catches for 104 yards against these Chargers back in Week 3, though, highlighting the potential impact he can have in this matchup. 

The Chargers seem considerably more likely to be focused on taking away the deep ball to Tyreek Hill -- something opposing defenses have actually done with a fair degree of success this season. Hill has only 16 catches of 20 or more yards so far this year, per Tru Media. He had 27 such receptions in 15 games last year. The Chargers' defense is designed to take those types of catches away from the opposing offense -- something it has done a pretty good job of this season, allowing the 10th-fewest 20-plus-yard Up gains in the league. 

Up front, the most important matchup is on the right side of Kansas City's offensive line, where Lucas Niang will have to deal with Joey Bosa, who is having another excellent season. Bosa has totaled 50 pressures this year, per Tru Media, the ninth-most in the NFL. His gets to the quarterback about 0.13 seconds faster than the league average rusher, per their tracking data, helping neutralize the idea of "just getting the ball out quickly." Mahomes will have to have Bosa in the corner of his eye all night, and be ready to deliver the ball underneath at a moment's notice to avoid Bosa wrecking the offensive game plan. 

When the Chargers have the ball

Important absences will likely have a dramatic effect on the matchup on this side of the ball: stud Chargers rookie left tackle Rashawn Slater and star Chiefs defensive lineman Chris Jones were each placed on the reserve/COVID-19 list this week, and neither will be in uniform on Thursday night. 

Slater's absence could change things quite a bit for the Chargers, who already have a noticeable weakness at right tackle, where Storm Norton has been filling in for Bryan Bulaga. Trey Pipkins has been slightly better when called upon this season than he was in a more regular role last year, but still represents an obvious downgrade. Frank Clark has not lived up to expectations as a pass rusher for the Chiefs since he was acquired and lavished with a monster contract extension, but he should have a considerable advantage rushing against Pipkins all night. Melvin Ingram has done quite well rushing across the line from Clark, and should be similarly set up for success against Norton. 

The pass rush may force the Chargers to return to more of the short passing game options than they have in recent weeks, where Justin Herbert has gotten back to slinging the ball all over the field with a bit more regularity. Luckily for them, Keenan Allen is set to return from the COVID list, while Chiefs slot corner L'Jarius Sneed is out. That should provide Herbert with a solid security blanket on underneath routes, which he can use to open things up a bit for the likes of Mike Williams, Jalen Guyton, and Josh Palmer over the top. 

Additionally, without Jones rushing up the middle, Herbert should have cleaner lanes to step up in or through the pocket, even if he can't escape to the outside and make quite as many freelancing plays on the move. Kansas City has morphed into a defensive-minded team in recent weeks, but playing without both Jones and Sneed changes a lot for the Chiefs in this matchup in particular. Still, Steve Spagnuolo's group is playing at an extremely high level at the moment, and the perimeter rush should pose a challenge for Herbert, as well as offensive coordinator Joe Lombardi. 

It's also possible that Chargers running back Austin Ekeler misses the game, though he is listed as questionable and did get in a limited practice earlier this week, so he has a chance of being on the field. If he plays, he provides Herbert with another valuable outlet for those quick throws, and his ability to create yardage after the catch could prove especially valuable. If he doesn't, L.A. will count on some combination of Justin Jackson and Joshua Kelley, neither of whom brings the same skill set. The bet here is that he plays his usual complement of snaps, helping the Chargers offense just enough to get over the top. 

Prediction: Chargers 27, Chiefs 23