COSTA MESA, Calif. -- Now in the twilight of his NFL career, Philip Rivers is having one of his worst seasons.

Rivers' 16 turnovers is third most in the league, and his 85.5 passer rating would be his lowest since 2007.

Even worse, Rivers has struggled in critical stretches, when the Chargers need him at his best. Rivers has a 73.8 passer rating in the fourth quarter, No. 28 in the NFL. He has a league-leading four interceptions in the red zone.

Rivers turns 38 on Dec. 8. He said that he'll regroup at the end of the year, taking some time to evaluate where he's at in his career and whether he wants to play in 2020, but he'd like to finish his career with the Chargers.

Rivers is in the final year of his contract, and the Los Angeles Chargers would have to sign him to a lucrative deal to keep the NC State product around for a couple of more years.

Asked if he would consider replacing Rivers at quarterback with backup Tyrod Taylor as the Chargers begin preparations for the Denver Broncos, Anthony Lynn said Rivers remains his quarterback.

"I'm not going to entertain that right now," Lynn said. "I'm evaluating everything, and right now Philip Rivers is our starting quarterback. I'm not going to single one position out; I'm looking at everybody. At 4-7, everybody could be doing something better."

Lynn also confirmed that Rivers is healthy.

Rivers and the Chargers have tough decisions to make at the end of the season. Pass protection has been a significant issue for the Chargers due to a patchwork offensive line, and they also have to evaluate a midseason change from Ken Whisenhunt to Shane Steichen at offensive coordinator.

Another part of the equation is continuing to grow a fan base in an ultra-competitive market while moving into brand-new SoFi Stadium in Inglewood next season, and ending the career of perhaps the greatest quarterback in franchise history the right way.

The Chargers' brass has maintained throughout the year that Rivers isn't going anywhere, but his uneven play this season will test the organization's resolve to move forward with him.

Rivers might be reluctant to move wife Tiffany and his nine kids from their San Diego home because of their attachment to the community. But if Rivers chooses to move on, there will be a robust market, with teams like the Broncos, Tennessee Titans, Carolina Panthers and Chicago Bears as possible landing spots in free agency.

Along with the play of Rivers, here are four other things to watch as the Chargers return from their bye week.

When will Derwin James be back?

While Lynn refuses to earmark a return date for his playmaking strong safety, the Florida State product’s season debut appears to be coming sooner rather than later.

James looked spry working on the field before the game against the Kansas City Chiefs in Mexico City. And according to Lynn, James stayed home to work at the team facility during the bye week.

"There's a chance," Lynn said. "I'm not going to say he'll be back, because I don't like to put a timetable on it. But there's a chance."

James was expected to have a three-to-four-month recovery after having surgery to repair a stress fracture in his right foot in September, which would put him on target to return in December.

However, with the Chargers not having much to play for, Lynn was asked if the team would consider shelving James until 2020.

"Why would we do that?" Lynn said. "If we have a healthy player as good as DJ, if he can play, he's going to play. But we're definitely not going to put him out there until he's ready."

Lynn's future?

Lynn is 25-18 overall during his three-year tenure as the team’s head coach. That includes a 9-7 campaign after starting 0-4 in his first season with the team and a 12-4 record last season, leading the Chargers to the postseason for the first time since 2013.

Chargers brass appreciates Lynn's unflinching way of leadership and the steadying influence he provides on a daily basis. No matter how the Chargers finish, it would be a surprise if Lynn departs.

Offense struggling, but defense playing lights out

While the Chargers have been inconsistent on offense, the defense has kept them in games and is the reason the Bolts have a plus-6 point differential this season.

The Chargers have allowed just 18.6 points per game, No. 8 in the NFL. The Bolts have given up only 205 passing yards per contest (No. 4 in the NFL) and have held opponents to a league-best 56.5% on field goal attempts.

In the loss to Kansas City, the Chargers held the Chiefs' high-powered offense to 24 points. The Chargers' consistent defensive play gives them a reason for optimism for next season.

Playoffs? You talking about playoffs?

The Chargers are losers of two straight and sitting at 4-7, so it seems absurd to mention the playoffs.

According to ESPN's NFL Football Power Index, the Chargers have a 0.4% chance to reach the postseason.

However, the Chargers remain just two games back of the final wild-card spot in the AFC and are about to face two scuffling teams in the Broncos and Jacksonville Jaguars.

Yes, they would need a lot of help and the possibility is remote at best, but the Chargers still have something to play for besides draft position.

"We're not tanking, guys," Lynn said. "We're 4-7, and last time I checked we have five games left. So we have a chance to have a winning record, and if we get some help, who knows?"