• The Chargers head into Sunday’s showdown with the Rams healthier on offense: receivers Ladd McConkey and Tre’ Harris, and tackle Joe Alt are all set to play.
• Although the Chargers are healthier, they still need to find ways to make Justin Herbert more productive. The Chargers are averaging an NFL-worst 15 points per game.

Although All-Pro safety Derwin James Jr. will miss his fourth consecutive game because of a hamstring injury, the winless Chargers are coming off their bye week with some much-needed reinforcements.

Wide receivers Ladd McConkey (concussion) and Tre’ Harris (hamstring) and offensive tackle Joe Alt (neck) are all set to play Sunday against the Rams at SoFi Stadium.

“It’s a good thing,” Chargers coach Jim Harbaugh said. “It’s good to have them back out there. Good work put in. Feel good about the preparation and feel like we’re in a good place, ready to go.”

Harris and McConkey have been the Chargers’ top two receivers when available this season. Harris leads the team in receptions (15), receiving yards (225) and targets (26), while McConkey is right behind him with 13 receptions for 200 yards on 18 targets.

And Alt’s return instantly improves the Chargers’ banged-up offensive line, which has allowed Justin Herbert — who carries a league-worst 29.4 quarterback rating — to be sacked nine times in the two games the offensive tackle has missed.

“Regrouping. Retooling. Thought it was a really good week of preparation,” Harbaugh said.

Offensive coordinator Mike McDaniel and his unit desperately need all hands on deck.

The Chargers are averaging a league-worst 15 points per game and are tied for the second-fewest yards per play (4.6).

“I spend all of my time focusing on the best plan for the players that we have available this week, to attack the defense we have,” McDaniel said. “And then you have to illustrate, in a good manner, what the vision is for how we’re going to play and improve the results.”

McConkey, Harris and Alt returning will help McDaniel’s cause, especially as wideout Brenen Thompson (quad/hamstring) remains out alongside key offensive linemen Rashawn Slater (ankle) and Kayode Awosika (fibula).

Meanwhile, the Chargers’ defense, which allows the eighth-fewest passing yards per game (206.2), must hold the fort again without James, who suffered a rehab setback.

“You can’t replace Derwin,” defensive coordinator Chris O’Leary said. “It’s not possible. He’s one of the best in the league, if not the best in the league.”

That task will be even harder if cornerbacks Donte Jackson and Rodney Shelley, who are both questionable with hamstring injuries, can’t play.

“For us, our message from the offseason to now is: team defense,” O’Leary said. “Play together. We’re not going to put too much on one guy’s plate. ... And that’s really just spiked, now that Derwin’s out.

“It’s just a group effort, and I think the guys have done a great job.”

O’Leary’s defense has bent but rarely broken all season.

McDaniel’s offense, however, could use a breakout performance. And with more of Herbert’s primary targets fully healthy, there’s no better time than Sunday.

“It was much-needed,” Herbert said of the bye.