Jack Del Rio will take the field as a head coach for the first time in almost two years as the Denver Broncos battle the San Diego Chargers in a pivotal AFC West matchup on Sunday afternoon at Qualcomm Stadium.

The Broncos have been without head coach John Fox since Saturday, after he took a leave of absence due to heart issues. The club turns to defensive coordinator Del Rio, who leads a Denver team hoping to keep pace with division-leading Kansas City. Fox was released from the hospital on Friday, but is expected to be out for 10 weeks, meaning Del Rio will be in charge for the remainder of the regular season, and perhaps a portion of the postseason.

Del Rio was fired by the Jacksonville Jaguars after going 3-9 through the first 12 weeks of the 2011 season. He spent nine years with the Jaguars, compiling a 73-63 record with one playoff victory in two appearances. 

Del Rio appears to have been thrown into the deep end. Major playoff implications are on the line for both clubs ahead of the showdown.

The Chargers are one of three AFC teams knotted at 4-4, just on the outside of the conference’s final Wild Card spot currently held by the New York Jets. A win for Denver would up the stakes even more for Week 11’s matchup with the Chiefs, which could decide the AFC West.

How Del Rio handles some of his new and old responsibilities might take a backseat for one of Week 10’s best quarterback matchups. Peyton Manning leads the NFL in every major passing category except for the one held by San Diego’s Philip Rivers.

Tops in the league for his accuracy, Rivers has completed 72.2 percent of his passes for 2,473 yards and 17 touchdowns to seven interceptions. Manning has kept the well-oiled Bronco offensive machine humming with 29 touchdowns and 2,919 yards, along with a 119.4 passer rating.

Rivers has made rookie receiver Keenan Allen his top target, with three 100-plus yard performances in the last four games. Allen has totaled 527 yards and three scores this season.

Manning, however, has looked more human the last two weeks, completing less than 60 percent of his passes in the lone 39-33 loss to Indianapolis, and tossing a season-high three interceptions and needing a 24-point comeback for a 45-21 victory over Washington before the bye.

Such an epic quarterback clash could spell trouble for both defenses, with Denver ranked 30th against the pass and San Diego 28th. The Broncos have balanced their league worst 15 passing touchdowns and 39 pass plays of 20-plus yards surrendered with 13 interceptions, but the Chargers have only forced five turnovers to 12 of their own miscues.

San Diego’s defense looked like it was set for huge tear after holding Indianapolis and Jacksonville to 15 combined points in consecutive weeks, but gave up 209 rushing yards and four touchdowns in last week’s 30-24 overtime loss to Washington.

Manning should have his full arsenal of receivers on Sunday, with touchdown-leader Wes Welker gradually upping his practice reps throughout the week until fully participating on Friday, according to the team’s official site. However, cornerback Champ Bailey remains out for a second straight game with his unforgiving foot injury, and starting safety Duke Ihenacho is questionable with an ankle injury. Bailey’s missed six games this year, and re-aggravated his injury in the Indianapolis loss.

Chargers outside linebacker Jarret Johnson is currently listed as questionable after missing practice on Friday, and receiver Eddie Royal is questionable for a third consecutive week due to a toe injury. Johnson is tied for the Chargers lead with three sacks, and Royals is knotted for fifth in the NFL with seven touchdown receptions.

Betting Odds: Denver favored by 7 points.

Over/Under: 58.5 points

Time: 4:25 p.m. ET

TV Channel: CBS

Where To Watch Online: NFL Sunday Ticket

Prediction: Denver 30, San Diego 17