SAN DIEGO, Calif. — To say the San Diego Chargers’ gang is almost all here is a good start. Or re-start.

The Chargers, fading away to 5-4 after a three-game losing streak, enjoyed their bye and now it’s time to get busy — plus welcome back some familiar faces.

And then play the Oakland Raiders, winless in nine games, on Sunday.

That is just the kind of welcome back tonic the Chargers may need.

But the Chargers’ bye was about getting well, too. That’s why some fresh players and mended bodies could greet the Raiders.

Running back Ryan Mathews is expected to practice and play this week. Barring any setbacks, Mathews could deliver a boost to a running game that is running on fumes.

Mathews, though, hasn’t played since Week 2 after injuring his knee. But if Mathews can help absorb the growing heat being put on Philip Rivers and find running lanes where others couldn’t, his return will be toasted.

“Ryan is obviously a dynamic player,” center Rich Ohrnberger said. “We are lucky to have him. The more weapons we can throw at them in these games the better.”

The Chargers could also get a slew of linebackers healthy. Melvin Ingram, Jerry Attaochu and Manti Te’o might be back.

Ingram, a pass-rushing former first-round pick, has been sidelined since the second week.

Te’o hasn’t played since Sept. 21 and would be a positive addition for a spotty run defense. Even more importantly, Te’o’s return could accelerate fellow inside linebacker Donald Butler’s quest to perform at a higher level.

Attaochu, the Chargers hope, can go where few Chargers have gone this season: the opposing pocket. The Chargers, with just 15 sacks, consistently fall short on putting heat on rival quarterbacks.

Finding a pass rush becomes more critical with rookie cornerback Jason Verrett’s status in question with a shoulder injury.

But at least another banged-up cornerback, Brandon Flowers, got a chance to exhale with the off week.

The Chargers are eager to resume a season that manufactured a five-game winning streak and appeared to have the playoffs as a destination.

Then the Chargers got bruised and played tougher teams, and the result has been a month of frowns.

So post-bye, the Chargers want to quickly shed their losing skid and get right for a challenging stretch run. It’s crunch time for the Chargers, with a peek ahead showing how pivotal Sunday’s game is.

With the Rams, Ravens, Patriots, Broncos, 49ers and Chiefs awaiting, the Chargers can’t falter against the Raiders.

“The great thing is,” coach Mike McCoy said, “there is a lot of football left.”

Notes: Cornerback Jason Verrett (shoulder) isn’t expected to practice this week. . . . Expected to rejoin practice are outside linebackers Melvin Ingram (hip) and Jerry Attaochu (hamstring), inside linebacker Manti Te’o (foot) and Ryan Mathews (knee) at running back. . . . Safety Jahleel Addae (concusion) remains out.

REPORT CARD AT THE BYE

–PASSING OFFENSE: A — Philip Rivers has stumbled a bit of late but the body of work is sensational. Rivers set an NFL mark with a passer rating of 120 in five consecutive games as the Chargers continue to lean on him as much as possible. He has 20 touchdowns against eight interceptions, with three picks coming in the shutout in Miami. Eddie Royal is having a solid year and he’s helped take up the slack for the injured Danny Woodhead on third downs. Ageless tight end Antonio Gates is just that as he’s among the NFL leaders with nine touchdown catches. Keenan Allen is productive, he’s just not scoring — one touchdown. The pass-blocking has been adequate, although against the speed rushers the tackles still have issues. Rivers is keen at extending plays by stepping up in the pocket, and he’s been exceptional on that count this season.

–RUSHING OFFENSE: F — The three-headed monster has been a disaster, with Danny Woodhead out for the year, Ryan Mathews missing five games and Donald Brown having issues with concussions. The Chargers are near, or at the bottom, in all the significant rushing categories. While the backs are missed, the lack of run-blocking must be noted as well. Especially in the interior, often backs have to make two or three moves to reach the line. The return of Mathews could help. Branden Oliver was a pleasant surprise in Mathews’ absence. But until the run-blocking improves, it won’t matter who’s carrying the football.

–PASSING DEFENSE: C — It’s average here and trending the direction not favorable for the Chargers. With seven games left the Chargers still haven’t figured out how to attack quarterbacks. With just 13 sacks and with no player with three, it’s been a sporadic run at the pocket for the pass-rushers. Dwight Freeney doesn’t have much left and hasn’t had a sack in two months. He’s having to play too much as injuries did a number on the depth. Cornerback Jason Verrett, the first-round pick, is a fine player. That makes his unavailability that much more frustrating as he’s had various injuries. Brandon Flowers gives the secondary experience and he’s been fine; injuries, though, have restricted him. Safety Eric Weddle again is the unit’s heart and soul. While not perfect this season, he remains their most consistent player.

–RUSHING DEFENSE: D — Hard to run a 3-4 without a dominant nose tackle and that’s the Chargers lot. Corey Liuget, at end, is having the best year on defense by someone other than Eric Weddle. But the linebackers are getting picked on in the running game — ranked No. 17 — as the blockers get to the second level much too often. Inside linebacker Donald Butler has been a shell of himself since signing a rich contract extension. He leads the team in tackles but also takes mystery routes and angles to ball-carries. Manti Te’o has also been missing from an inside run defense that too often gets pushed around.

–SPECIAL TEAMS: C — Someday, the Chargers will unearth a return game. Until then, it’s more of the same as the special teams seldom provide envious field position with their returns. K Nick Novak is having another solid season, hitting all 14 field-goal attempts. Punter Mike Scifres is consistent as ever with a nearly 40-yard net. The coverage units have been fine.

COACHING: C — Mike McCoy had this baby rolling, then the wheels came off. To his credit he hasn’t played the injury card but what the ailments did reveal was a considerable drop off between the starters and the backups. McCoy still has the team’s belief that he can flip this the right way to keep the playoffs hopes alive. But it was a disturbing loss the last time they played, a blanking in Miami in which the team showed little heart. Defensively the tackling remains a season-long issue and coordinator John Pagano promises it is addressed in practice. But there’s only so many ways Pagano can draw up a pass rush, and to date, he hasn’t had much luck. McCoy gets the benefit of having a veteran team full of leaders to help him keep everyone focused. But doubt has crept into the locker room, and it’s imperative the Chargers win quickly to keep the faith that this will be more than a disappointing season.